JP3140987B2 - Transmitting device, receiving device, communication device, and modem signal transmitting / receiving method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

(Contents) Technical field to which the invention pertains Prior art (FIGS. 31 to 33) Problems to be Solved by the Invention Means for Solving the Problems (FIGS. 1 to 3) Embodiment of the Invention First Embodiment Description of Embodiment (FIGS. 4 to 10) Description of Second Embodiment (FIGS. 11 to 14) Description of Third Embodiment (FIGS. 15 to 23, FIG. 31) Modification of Third Embodiment (FIGS. 24 and 25) ・ Description of the fourth embodiment (FIGS. 26 to 29, FIG. 31) ・ Description of a modification of the fourth embodiment (FIG. 30) ・ Other effects of the invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention converts an analog signal such as voice, modem carrier, etc. into digital data,
A modem signal transmission / reception device that receives data received from an opposite device while transmitting it together with dial information, etc., and in particular, performs communication between devices connected via a toll network connected via a metal line or an in-band ringer. The present invention relates to a transmitting device, a receiving device, a communication device, and a method for transmitting and receiving a modem signal, which are suitable for use in performing.

[0003]

2. Description of the Related Art Generally, a telephone or FAX terminal accommodated in a private branch exchange (PBX) and a telephone or FAX terminal accommodated in another private branch exchange are connected via a dedicated line such as a metal line. In performing communication, as shown in FIG. 31, an in-band ringer (IBR) and a modem (modulator / demodulator) are interposed on a dedicated line connecting these private branch exchanges.

That is, as shown in FIG. 31, a private branch exchange 103 includes an in-band ringer 104 and a modem 105.
Is connected to a dedicated line 111 as a toll network through
The private branch exchange 108 is connected to a dedicated line 111 via an in-band ringer 107 and a modem 106. Here, the in-band ringer 104 performs signal conversion processing such as dial information between the private branch exchange 103 and the dedicated line 111, and similarly, the in-band ringer 107 performs communication between the private branch exchange 108 and the dedicated line 111. It performs signal conversion processing such as dial information between
In both inband ringers 104 and 107,
As a dial signal to be output to the dedicated line 111, for example, a single tone signal of about 3 kHz is used.

[0005] The modem 105 is connected to the opposite modem 1.
06 is connected via a dedicated line 111 to transmit analog signals transmitted from the terminals 101 and 102 on the private branch exchange 103 side to the modem 106, while transmitting analog signals from terminals 109 and 110 on the opposite private branch exchange 108 side. The signal is received. Similarly, modem 106
Transmits the transmission analog signals from the terminals 109 and 110 of the private branch exchange 108 to the modem 105,
It receives analog signals from the terminals 101 and 102 on the side of the private branch exchange 103 opposite thereto.

[0006] Thus, a terminal housed in one private branch exchange 103 (for example, FAX terminal 101 or telephone terminal 10).
2) and a terminal (for example, FAX terminal 109 or telephone terminal 110) accommodated in the other private branch exchange 108,
In-band ringers 104, 107, modems 105, 10
6 and the dedicated line 111, communication can be performed.

Here, each of the modems 105 and 106 has a modem signal transmitting section 112 and a modem signal receiving section 119 as shown in FIGS. 32 and 33 in detail. Here, as shown in FIG. 32, the modem signal transmitting unit 112 in the modem 105
3, demodulation section 114, carrier generation section 115, roll-off filter 116, determination section 117, and modem transmission processing section 1
(Hereinafter, the configuration of the modem signal transmitting unit 112 is described focusing on the modem 105, but the modem 106 has the same configuration.)

[0008] That is, the A / D conversion unit 113 is connected to the telephone terminal 1
01 or an analog signal (for example, a voice band of 0.3 to 3.4 kHz) input from the FAX terminal 102 via the private branch exchange 103 and the in-band ringer 104,
For example, it is converted into a digital signal at a sample rate of about 12 kHz. Also, the demodulation unit 114 performs A / D
The digital signal from the converter 113 is provided with angle information having a carrier frequency of, for example, about 1700 Hz generated by the carrier generator 115 for each predetermined angle, thereby demodulating an analog signal into a baseband signal.

Further, the roll-off filter 116 performs a decimation process on the demodulated signal from the demodulation unit 114 to obtain a sample rate (about 12 kHz).
Is converted into a symbol rate (for example, about 3000 Hz) to reduce the amount of information, and has a function as a filter for decimation processing.

Note that the 1700 Hz frequency band generated by the above-described carrier generation unit 115 and the symbol rate 3000 Hz converted by the roll-off filter 116 are used.
The frequency band of the voice and recommendation V. 29, V.S. 22bis
And V. It can be commonly used in consideration of the frequency band set at 32 or the like. In particular, the demodulation frequency band of 1700 Hz is described in Recommendation V.7. 29 corresponds to the carrier frequency of G3 FAX.

A determination unit 117 receives the signal subjected to the decimation processing by the roll-off filter 116, determines the coordinates on a two-dimensional plane, and converts the signal demodulated into a baseband signal into a dedicated line. In this case, the amount of information required to be transmitted on the terminal 111 is determined. further,
The modem transmission processing unit 118 converts the digital data as the determination result from the determination unit 117
A modem process such as a natural conversion, a sum, a signal point generation, a roll-off filter process, a modulation process, and a D / A conversion process is performed. A modem signal (analog signal) subjected to such a modem process is The data is transmitted to the modem 106 via the dedicated line 111.

Also, the modem signal receiving unit 1 of the modem 106
Reference numeral 19 denotes the modem reception processing unit 12 as shown in FIG.
0, a roll-off filter 121, a demodulation unit 122, a carrier generation unit 123, and a D / A conversion unit 124 (hereinafter, a modem signal reception unit 119).
Is described focusing on the modem 106, but the modem 105 also has a similar configuration.)

That is, the modem reception processing unit 120 performs A / D conversion processing, demodulation processing, roll-off filter processing, automatic gain processing on a signal received from the modem transmission processing unit 118 of the opposite modem 105 via the dedicated line 111. It performs inverse modem processing such as control, automatic equalization, carrier phase correction, signal point determination, and difference. Further, the roll-off filter 121 performs an interpolation process (a process corresponding to the decimation process in the transmission-side loaf-off filter 116) on the signal subjected to the inverse modem process from the modem reception processing unit 37. It has a function as a filter for poration processing.

That is, the symbol processing (for example, 3000H
The amount of information can be restored by converting from about z) to a sample rate (about 12 kHz). Further, the modulation unit 122 outputs a signal from the roll-off filter 121 to the carrier generation unit 1.
The baseband signal is modulated by a carrier frequency signal of about 1700 Hz generated in 23 to make the baseband signal a signal of the original frequency band (for example, 0.3 to 3.4 kHz for an audio signal).

Further, the D / A conversion section 124 includes a modulation section 1
The digital signal modulated at 22 is converted into an analog signal, and the converted analog signal is output to the in-band ringer 107 as an output of the modem signal receiving unit 119. With such a configuration, in the communication system as shown in FIG. 31 described above, for example, between the telephone terminals 102 and 110 or the FAX terminal 101,
When communication is performed between the private branch exchanges 109 and 109, dial information subjected to signal conversion by the in-band ringers 104 and 107 is exchanged between the private branch exchanges 103 and 108, and analog signals such as voice signals and fax signals are transmitted to the modems 105 and 1 respectively.
06 and the dedicated line 111.

For example, a voice signal as an analog signal from the telephone terminal 101 (or an FA signal from the FAX terminal 102)
X signal), the A / D converter 11 of the modem 105
The digital signal is converted into a digital signal at 3, demodulated by the demodulation unit 114, and the coordinates are determined by the determination unit 117.
The digital data as a result of the determination is subjected to modem processing by a modem transmission processing section 118 and then output to the other party's telephone terminal 110 via the dedicated line 111, the modem 106, the in-band ringer 107 and the private branch exchange 108. You.

The determination unit 117 of the modem signal transmission unit 112 of the modem 105 determines a tone signal (for example, about 3 kHz) from the in-band ringer 104 in addition to the analog signal as described above. In-band ringer 1 via dedicated line 111
07. The in-band ringer 107 recognizes a tone signal from the in-band ringer 104 on the transmission side.

[0018]

However, in the communication system shown in FIG.
In 106, since the number of determination points constituting the determination surface in the determination unit 117 is limited, when transmitting the tone signal, if the output of the roll-off filter 116 is directly determined, the S / N ratio required for the tone signal is determined. (Signal-to-noise ratio) may not be satisfied.

In other words, the inband ringer 10 on the originating side
If the output of the roll-off filter for the tone signal from 4 (107) is determined by the determination unit 117 as it is, it may not be possible to make a determination with a determination error that satisfies the required S / N ratio. In this case,
In the in-band ringer 107 (104) on the receiving side,
There is a problem that the tone signal from the calling side cannot be recognized, and the dial information from the transmitting side cannot be accurately notified to the receiving side.

The present invention has been made in view of the above problems, and transmits a pure tone signal that satisfies a required S / N ratio, thereby reliably recognizing the tone signal on the receiving side. It is an object of the present invention to provide a transmitting device, a receiving device, a communication device, and a method for transmitting and receiving a modem signal.

[0021]

FIG. 1 is a block diagram showing the principle of the present invention. In FIG. 1, reference numeral 201 denotes a communication device, which converts an analog signal into a digital signal and sends it out. A transmission unit 202 and a reception unit 203 that converts a received digital signal into an analog signal are provided.

Here, the transmission section 202 includes a first frequency shift section 202A for performing a frequency shift on the input analog signal so as to convert a tone signal having a specific frequency into a DC signal, and a first frequency shift section 202A. It is configured to include a coordinate determination unit 202B that determines the coordinates of the signal output from the unit 202A on the two-dimensional coordinate plane. Also,
Receiving unit 203 to a digital signal received, that is configured to include a second frequency shift unit 203A for performing the frequency shift as to convert the tone signals having a specific frequency DC signal.

By focusing on the respective functions of the transmitting unit 202 and the receiving unit 203 constituting the communication device 201, the transmitting unit 202 is simply configured as a transmitting device, and the receiving unit is simply configured as a receiving device. You can also. In other words, the transmitting unit 202 as a transmitting device
Is to determine the coordinates of the input analog signal on a two-dimensional coordinate plane, and to transmit the signal whose coordinates have been determined as a digital signal, wherein a tone signal with a single frequency is a DC signal. A frequency shift unit 202A that performs a frequency shift on the input analog signal, and a frequency shift unit (first frequency shift unit) 2
A coordinate determination unit 202B that determines the coordinates on the two-dimensional coordinate plane of the analog signal subjected to the frequency shift by 02A.
That it has been configured to include a door.

The transmitting unit 20 as the above-described transmitting device
2, a coordinate determination result is input from the coordinate determination unit 202B, and a determination point determination unit that determines whether or not the same determination result is continuous. By using a phase difference detection unit that detects a phase difference between the phase of the applied signal and the phase of the coordinate determination unit output signal, and a phase difference detected by the phase difference detection unit, the frequency shift unit 202A It is configured to include a phase correction unit that outputs to the phase coordinate determination unit 202B corrects the signals which the frequency shifting is performed also Ru can.

Further, a demodulation section for demodulating the input analog signal with a carrier signal having a specific frequency is provided, and a frequency shift section 202A corresponds to a difference between the frequency of the tone signal and the frequency of the carrier signal. to minute, but it may also constitute the input analog signal to a frequency shift. Further, in accordance with the single frequency of the tone signal contained in the analog signal the input, Ru can also be configured to be set the frequency shift amount in the frequency shift unit 202A.

Further, the receiving section 2 as the above-mentioned receiving apparatus
Reference numeral 03 denotes a frequency shift unit (second frequency shift unit) that performs a frequency shift on the received digital signal such that a tone signal having a specific frequency is reproduced from the DC signal.
203A and a frequency shift unit 203B.
A digital signal frequency shift is performed Ru can also equipped with a digital / analog converter for converting into an analog signal by.

The receiving section 203 as a receiving apparatus includes a modulating section for modulating a digital signal output from the frequency shifting section 203A with a carrier signal having a specific frequency. frequency component corresponding to the difference between the frequency of the carrier signal, Ru can be configured to perform a frequency shift with respect to the digital signal.

The above-mentioned second frequency shift section 203A
Frequency shift due to the that-out <br/> in that corresponding to inverse frequency shift of the frequency shift by the first frequency shift unit 202A. Further, in the communication device 201 described above, a demodulation unit that demodulates an input analog signal with a first carrier signal having a specific frequency and outputs a demodulated signal to a first frequency shift unit 202A, A signal output from the second frequency shift unit 203A is modulated by a second carrier signal having a specific frequency, and a modulation unit that outputs a modulated signal is provided.
Is configured to shift the frequency of the input signal by a frequency corresponding to the difference between the frequency of the tone signal and the frequency of the first carrier signal, and the second frequency shift unit 203A frequency component corresponding to the difference between the frequency of the second carrier signal of the tone signal, but it may also be configured to perform a frequency shift relative to the input signal.

Further, in the above-described communication device 201, the judgment signal output from the coordinate judging section 202B is input, and the judgment point judgment for judging whether or not the input judgment signals are continuously the same judgment result is performed. And the determination point determination unit determines that the same determination signal is continuously generated, the phase of the signal output from the frequency shift unit and the phase of the signal output from the coordinate determination unit are determined. It can also be configured to include a phase difference detection unit for obtaining a phase difference, and a phase correction unit for correcting the phase of a signal output from the frequency shift unit based on the phase difference obtained by the phase difference detection unit. You.

FIG. 2 is a block diagram showing the principle of the present invention. In FIG. 2, reference numeral 12 denotes a modem signal transmitting / receiving device. The modem signal transmitting / receiving device 12 includes a modem signal transmitting unit 13 and a modem signal receiving unit 14. It is configured with. Here, the modem signal transmitting unit 13 includes the demodulating unit 2,
It comprises a phase difference calculating section 3, a transmitting-side single tone determining section 4, a coordinate determining section 5, and a signal transmitting section 6.

That is, the demodulation unit 2 demodulates a transmission signal at a predetermined carrier frequency, and the phase difference calculation unit 3 calculates a phase difference between successive demodulation signals from the demodulation unit 3. Transmitter single tone determination unit 4
Is for determining whether or not the demodulated signal demodulated by the demodulation unit 2 is a single tone. Also, the coordinate determination unit 5
Performs coordinate determination on either the demodulated signal from the demodulator 2 or the phase difference signal from the phase difference calculator 3. More specifically, if the result of the determination by the transmission-side single-tone determination section 4 is that the demodulated signal is not a single tone, the coordinate determination section 5 performs coordinate determination on the demodulated signal from the demodulation section 2, Is a single tone, the coordinate determination unit 5 performs the coordinate determination on the phase difference signal from the phase difference calculation unit 3.

The signal transmission section 6 transmits the result of the determination by the coordinate determination section 5. The modem signal receiving section 14 includes a signal receiving section 8, a phase sum calculating section 9, a receiving-side single tone determining section 10, and a modulating section 11. Here, the signal receiving unit 8 is connected to the opposing device 1.
5 (for example, a modem signal transmitting and receiving device
The phase sum calculator 9 calculates the phase sum of successive reception signals from the signal receiver 8 by receiving the transmission signal from the modem signal transmitter 17) via the line 18. The receiving-side single-tone determining unit 10 determines whether a received signal is a single tone.

Further, the modulating section 11 modulates either the received signal from the signal receiving section 8 or the phase sum signal from the phase sum calculating section 9.
Specifically, based on the determination result in the receiving-side single-tone determining unit 10, if the received signal is not a single tone,
While the modulation unit 11 modulates the received signal, if it is determined that the received signal is a single tone, the modulation unit 1
That it has adapted to modulate the phase sum signal from the phase sum calculation unit 9 in 1.

[0034] Incidentally, if attention is paid only to the modem signal transmitting unit 13 and a modem signal receiver 14 discussed above, respectively, simply Ru can also be configured as a modem signal transmitter and a modem signal receiver. In this case, when the transmission data is subjected to coordinate determination and transmitted by using the modem signal transmission device 13, the transmission-side single-tone determination unit 4 determines whether the transmission data is a single tone. Is determined.

Here, when it is determined that the transmission data is a single tone, the phase difference calculation unit 3 calculates the phase difference between successive transmission data, and the coordinate determination unit 5 calculates the phase difference. The result is subjected to coordinate determination and transmitted. When it is determined that the transmission data is a signal other than a single tone, the coordinate determination unit 5 performs a coordinate determination on the transmission data and transmits the data using the signal transmission unit 6.

When the opposing device 15 has the same configuration as the above-described modem signal transmitting / receiving device 12, when receiving the transmission data from the signal transmission unit 6 as the reception data, A receiving-side single-tone determining unit (not shown) in the receiving unit 16 determines whether the received data is a single tone. Here, when it is determined that the received data is a single tone, the phase sum calculation unit calculates the phase sum of the continuous reception data, and the modulation unit modulates the calculation result of the phase sum. together, the case where the received data is determined to be a signal other than a single tone, a modulation section, modulation for the received data.

The transmission-side single tone determination unit 4
Can be configured to determine that the demodulated signal input continuously for a predetermined number of times is a single tone when the level of the demodulated signal input continuously for a predetermined number of times is constant. >-out that. Specifically, a gain control unit that performs gain control on the demodulated signal based on the maximum level information of the demodulated signal continuously input a predetermined number of times is provided at a stage preceding the phase difference calculating unit 3. The one-tone determining unit 4 determines whether or not the level of the demodulated signal input continuously for a predetermined number of times is constant based on the gain control information from the gain control unit. demodulated signal input to the Ru can be configured to determine that a single tone.

The transmitting-side single-tone determining section 4 is configured to determine that the demodulated signal is a single tone when the phase difference of the demodulated signal input continuously a predetermined number of times is constant. Ru can also. Further, the above-described receiving-side single-tone determining unit 10 determines that the received signal input continuously a predetermined number of times is a single tone when the level of the received signal input continuously a predetermined number of times is constant. Ru can be configured to determine.

More specifically, the receiving-side single-tone determining unit 10
Is determined based on gain control information from the opposing device 15 (for example, a modem signal transmitting / receiving device having the same configuration as the above-mentioned code 12) whether the level of the received signal input continuously a predetermined number of times is constant. It is also possible to determine whether or not the received signal input continuously a predetermined number of times is a single tone when the level is constant.
You.

The receiving-side single-tone determining unit 10 is configured to determine that the received signal is a single tone when the phase difference between the received signals input continuously a predetermined number of times is constant. Ru can also. FIG. 3 is also a block diagram showing the principle of the present invention. In FIG. 2, reference numeral 20 denotes a modem signal transmitting / receiving device. This modem signal transmitting / receiving device 20 also includes a modem signal transmitting unit 21 and a modem signal receiving unit 22. It is configured.

Here, the modem signal transmitting section 21 includes a demodulating section 23, a phase difference calculating section 24, a coordinate determining section 25, a phase error detecting section 26, a transmitting-side single tone determining section 27, and a signal transmitting section 28. It is configured. That is, the demodulation unit 23
Is for demodulating a transmission signal at a predetermined carrier frequency, a phase difference calculating unit 24 is for calculating a phase difference in a continuous demodulated signal from the demodulating unit 23, and a coordinate determining unit 25 is for The coordinates from the output from the arithmetic unit 24 are determined.
Is for transmitting the determination result in the coordinate determination unit 25.

The phase error detector 26 detects a phase error based on the coordinate determination result from the coordinate determiner 25 and the phase difference calculation result from the phase difference calculator 24. The tone determination unit 27 determines whether the demodulated signal input to the phase difference calculation unit 24 is a single tone. Thereby, when the transmitting-side single tone determining unit 27 determines that the demodulated signal is not a single tone, the phase error information detected by the phase error detecting unit 26 is fed back to the phase difference calculating unit 24. On the other hand, when it is determined that the demodulated signal is a single tone, the feedback of the phase error information detected by the phase error detection unit 26 to the phase difference calculation unit 24 is stopped.

The modem signal receiving section 22 is connected to an opposite device (for example, the modem signal transmitting / receiving section 3 in the modem signal transmitting / receiving apparatus 33 having the same configuration as the reference numeral 20 described above).
From 5), a signal receiving unit 29 that receives a transmission signal including a transmission signal whose phase error has been corrected via the line 19, and a phase sum that calculates a phase sum of successive reception signals from the signal receiving unit 29 an arithmetic unit 30, that is configured to include a modulation unit 31 that performs modulation processing for the phase sum, which is calculated by the phase sum calculation unit 30.

The above-mentioned modem transmitting / receiving device 12 can be simply configured as a modem signal transmitting device having the same function as the modem signal transmitting portion 21 and a modem signal having the same function as the modem signal receiving portion 22. Ru can also be configured as a receiving device. In this case, when the coordinate determination unit 25 of the modem signal transmission device 21 performs the coordinate determination on the transmission data and transmits the data from the signal transmission unit 28, the transmission-side single tone determination unit 27
It is determined whether or not the transmission data is a single tone.

Here, when it is determined that the transmission data is a single tone, the phase difference between the continuous transmission data is calculated, the coordinates of the calculation result of the phase difference are determined, and the transmission data is transmitted. Is determined to be a signal other than a single tone, the phase difference of the continuous transmission data is calculated, and the coordinates of the calculation result of the phase difference are determined and transmitted. An error between the calculation result of the phase difference and the result of the coordinate determination is extracted, and the error is corrected at the time of calculating the phase difference for the next transmission data.

When the modem signal receiving section 34 of the device 33 facing the above-mentioned modem signal transmitting apparatus 21 has the same configuration as the above-mentioned modem signal receiving section 22, the transmission data is received as the reception data. when, in the phase sum calculation unit, after calculating the phase sum of the received continuous data, modulated by the modulation unit. Note that, when the level of the demodulated signal input continuously for a predetermined number of times is constant, the demodulation signal input continuously for a predetermined number of times is a single tone. Ru can be configured to determine.

Specifically, a gain control section for performing gain control on the demodulated signal based on the maximum level information of the demodulated signal input continuously a predetermined number of times is provided at a stage preceding the phase difference calculating section 24, Transmitter single tone determination unit 27
Based on the gain control information from the gain control unit, it is determined whether the level of the demodulated signal input continuously for a predetermined number of times is constant, and if the level is constant, it is input continuously for a predetermined number of times. demodulated signal Ru can be configured to determine that a single tone.

The transmitting-side single-tone determining section 27 is configured to determine that the demodulated signal is a single tone when the phase difference between the demodulated signals input continuously a predetermined number of times is constant. Ru can also. The modem signal transmission / reception method of the present invention calculates a phase difference between continuous transmission data for transmission data composed of a single tone, performs coordinate determination on the calculation result of the phase difference, and transmits the transmission data. Is received as received data,
It is characterized in that a phase sum of successive received data is calculated, and the calculation result of the phase sum is modulated.

[0049]

Embodiments of the present invention will be described below with reference to the drawings. (A) Description of First Embodiment FIG. 4 is a block diagram showing a transmission unit 210 constituting a modem according to the first embodiment of the present invention, and FIG. 5 is constituting a modem according to the first embodiment of the present invention. It is a block diagram showing a receiving part.

In the modem according to the first embodiment,
It can be used as the modems 105 and 106 in the communication system as shown in FIG. That is, the first
If the modem as the communication device according to the embodiment is applied, for example, as the modem 105 (disposed at the position of the modem 105), the private branch exchange 10 is transmitted by the transmission unit 210 shown in FIG.
3 is transmitted to the modem 106 via the dedicated line 111 to the modem 106, and the receiving unit 220 shown in FIG. For analog signals from

In transmitting section 210, a single tone from in-band ringer 104 can be demodulated and determined, and the like, and transmitted. In receiving section 220, a single tone from in-band ringer 107 can be transmitted. The tone (judgment data) can be decoded, modulated, and the like and output to the in-band ringer 104.

As described above, the modem as the communication device according to the first embodiment has the transmission unit 210 as shown in FIG. 4 and the reception unit 50 as shown in FIG. 5 in detail. The configuration of the modem as the communication device according to the embodiment is also described in detail focusing on the case where the modem is arranged at the position of the modem 105 shown in FIG. 31. It has the configuration of

Here, the transmission unit 210 is provided with the A / D conversion unit 2
11, a demodulation section 212, a carrier generation section 213, a roll-off filter 214, a frequency shift section (first frequency shift section) 215, a coordinate determination section 216, and a modem transmission processing section (signal transmission section) 217. The analog signal is converted into an A / D converter 211, a demodulator 212, a loaf-off filter, a frequency shifter 215, and a coordinate determiner 21.
6, after passing through each section in the order of the modem transmission processing section 217,
It is sent to the line 111.

The A / D converter 211 includes a telephone terminal, a facsimile
An analog signal (for example, a band of 0.3 to 3.4 kHz) input from the terminal or the in-band ringer 104 is input, and is converted into a digital signal at a sample rate of about 12 kHz, for example. Also, the demodulation unit 212
The digital data output from the / D conversion unit 211 is
The passband signal is converted into a baseband signal by demodulating with a carrier signal having a frequency of 1700 Hz. Note that the carrier signal is transmitted from the carrier generation unit 2.
13 is generated.

The roll-off filter 214 is
2 is to perform a decimation process on the demodulated signal output from 2. Here, the sample rate (12k
Hz, 4 samples / symbol) to the symbol rate (3
000 Hz, 1 sample / symbol) to reduce the information amount of the demodulated signal, and the roll-off filter 214 functions as a filter for decimation processing.

Here, the signal output from the roll-off filter 214 is input to the frequency shift unit 215.
The frequency shift unit 215 controls the roll-off filter 214 so that the tone signal of a single frequency becomes a DC signal.
Is subjected to a frequency shift. For example, 3000 as an in-band ringer
When a single tone signal of 1 Hz is used, the difference between the frequency of the tone signal of 3000 Hz and the frequency of the carrier signal of 1700 Hz (-1300) is used as the frequency shift amount.
Hz), the signal input to the frequency shift unit 215 is frequency-shifted.

By performing this processing, the 3000 Hz tone signal output from frequency shift section 215 is converted to a DC signal. FIG. 6 is a diagram illustrating an equivalent circuit of the frequency shift unit 215. The frequency shift unit 215 includes a frequency shift operation unit 215-1, a rounding unit 215-2, and a gain adjustment unit 215-3. ing. In FIG. 6, RRFR indicates a real part component of the signal input to the frequency shift unit 215, and similarly, RRFI indicates an imaginary part component of the signal input to the frequency shift unit 215.

Here, the frequency shift calculator 215-1
Represents the real component RRFR of the signal input from the roll-off filter 214 as cos θ ₀ and the imaginary component RRFI as sin θ
_0, the these components cos theta _0, sin theta ₀ for substantially the following equation (1), by performing a calculation of a trigonometric function shown in (2), and performs frequency-shift operation. Here, ω is an angular velocity including information on the frequency f to be shifted (ω = f / 2π).

Cos (θ ₀ −ω) = cos θ ₀ · cos ω + sin θ ₀ · sin ω (1) sin (θ ₀ −ω) = sin θ ₀ · cos ω−cos θ ₀ · sin ω (2 That is, the real and imaginary components of the signal input to the frequency shift unit 215 are respectively multiplied by the carrier signals cos ω and −sin ω for performing the frequency shift. Note that these carrier signals have the same frequency of 1300 Hz as the frequency shift amount in the case of the first embodiment. The frequency of the carrier signal can be appropriately changed according to a desired frequency shift amount.

The real component and the imaginary component of the input signal multiplied by the carrier signals cos ω and −sin ω are subsequently added by an adder. The difference between the real part component multiplied by cos ω and the imaginary part component multiplied by −sin ω is obtained. On the other hand, the real part component multiplied by −sin ω is added to the imaginary part component multiplied by cos ω.

The rounding section 215-2 performs a rounding process on the operation result from the frequency shift operation section 215-1. More specifically, a rounding coefficient RN is added to each of the addition results of the real part component and the imaginary part component.
The frequency shift of 00 Hz is completed. The frequency-shifted signal is supplied to a gain adjustment unit (Gain adjustment in the figure) 215-
3, after adjusting the amplitude, the real component R
RFR 'and the imaginary part component RRFI' are output from the frequency shift.

FIGS. 7 to 9 are diagrams for explaining the operation of the frequency shift unit 215. FIG. FIG. 7 is a diagram illustrating an analog signal output from the roll-off filter 214. In this case, a 3000 Hz tone signal is shown. Also shown in (S1)-
A point (S3) indicates a symbol (sample value) obtained as a result of sampling a single tone signal.

As described above, the signal output from the roll-off filter 214 has a symbol rate of 3000 Hz. This matches the frequency of the tone signal. Therefore, the signal (sample value of the tone signal) output from the roll-off filter 214 has a constant phase difference θ.
Is input to the frequency shift section 215. Further, since the symbol rate and the frequency of the tone signal are constant, the amplitude of the symbol of the tone signal output from the roll-off filter 214 is the same. Accordingly, the signal at the output of the roll-off filter 214 appears to rotate on the circumference illustrated in FIG.

FIG. 8 is a diagram showing the tone signal after the frequency shift. As described above, since a single tone signal having a frequency of 3000 Hz is converted into a DC signal by performing the frequency shift, the frequency shift unit 21
The phase difference of the output signal from the output signal 5 becomes zero, and the output signal is always output as the same point data. FIG. 8 shows that a signal corresponding to a single tone signal is arranged on the X axis.

That is, the signal points from the roll-off filter 214 are inputted with a constant phase difference θ as shown in points (S1) to (S3) shown in FIG. By performing the frequency shift at
As shown in FIG. 8, the data is output as one point of data (S4). FIG. 9 shows a state after the coordinates of the output signal from the frequency shift unit 215 on the two-dimensional coordinate plane are determined. As shown in FIG. 8, since the tone signal is converted into a DC signal and the amplitude and the phase are always the same, the coordinates of the determination point determined on the two-dimensional plane are always constant at the point (S5). . In the case of FIG. 9, the determination points are arranged at the same positions as the positions where the DC signals are arranged in FIG.

FIG. 10 is a diagram showing an example of the arrangement of judgment points according to the present embodiment. In the case of the determination surface 48A shown in FIG. 10, a total of 63 determination points are arranged. On the determination surface 48A, one determination point is arranged at the center of a regular hexagonal area. Here, in order to prevent a determination error from occurring, it is most desirable to determine the signal point arrangement and the like so that the DC signal determined in FIG. 9 corresponds to any one of the determination points in FIG. .

The signal output from the coordinate determination unit 216 is
A well-known gray / natural conversion or modulation process is performed in the modem transmission processing unit 217, and the modulated signal is transmitted to the opposing modem via a dedicated line. On the other hand, as shown in FIG. 5, the reception unit 220 includes a modem reception processing unit (signal reception unit) 221, a frequency reverse shift unit (frequency shift unit, second frequency shift unit) 222, a roll-off filter 223, and a modulation unit. A section 224, a carrier generation section 225 and a D / A conversion section 226 are provided. The signal input via the line passes through the respective sections in the order of a modem reception processing section 221, a frequency reverse shift section 222, a roll-off filter 223, a modulation section 224, and a D / A conversion section 226, and becomes an analog signal. Is output.

The signal received via the line is subjected to demodulation processing and the like by modem reception processing section 221 and then input to frequency reverse shift section 222. Note that the demodulation processing can apply the well-known technique implemented by the conventional modem as it is. Here, the frequency reverse shift unit 22
Numeral 2 is for performing a frequency shift on the received digital signal so that a tone signal having a specific frequency is reproduced from the DC signal.

Specifically, the frequency reverse shift section 222
The processing is completely opposite to the frequency shift by the transmission unit. Since the tone signal having a frequency of 3000 Hz is converted into a DC signal by the frequency shift unit of the transmitting unit, it is necessary to reproduce the 3000 Hz tone signal by applying a frequency reverse shift to the DC signal received via the line. There is.

Since the transmitting section has performed a frequency shift of -1300 Hz, the receiving section 220 has +1300 Hz.
A frequency shift of z is performed. That is, the state of the signal input to the frequency reverse shift unit 222 of the receiving unit 220 is as shown in FIG. 8, and the signal in the state where the frequency reverse shift has been performed (the output signal from the frequency reverse shift unit 222) is shown in FIG. It is in the state.

In other words, the frequency reverse shift section 222
The received digital signal is frequency-shifted by a frequency corresponding to the difference between the frequency of the tone signal and the frequency of the carrier signal. The signal output from the frequency reverse shift unit 222 is subsequently input to the roll-off filter 223. The roll-off filter 223 of the receiving unit 220 performs an interpolation process on the input signal. This interpolation processing corresponds to the decimation processing performed by the transmission unit.

A process of converting the symbol rate of 3000 Hz to the sample rate of 12 kHz is performed by the interpolation filter processing by the roll-off filter 223, whereby the information amount can be restored. The output of the roll-off filter 223 is subsequently input to the modulation unit 224. The modulation unit 224 modulates a signal input by a 1700 Hz carrier signal generated by the carrier generation unit 225 to convert the baseband signal into a passband signal (0.3 to 3.4 k for an audio signal).
Hz).

The output of the modulator 224 is input to the D / A converter 226, where the digital signal is output after being converted into the original analog signal. The output from the D / A converter 226 is input to an in-band ringer not shown in FIG. By adopting such a configuration, a single tone signal of a specific frequency (in this case, 3000 Hz) is converted into a DC signal by frequency shift and coordinate determination is performed.
Since the received DC signal is reproduced to the original tone signal by frequency reverse shift, it is possible to reduce the determination error in coordinate determination as much as possible, and the tone used for the in-band ringer transmitted via the dedicated line is used. The signal can be transmitted without lowering the S / N ratio so that the signal is not distorted, and the tone signal can be reliably recognized in the receiving device.

As described above, according to the first embodiment of the present invention, the transmission unit 210 is provided with the frequency shift unit 215 and the coordinate determination unit 216, so that the modem 1 shown in FIG.
When used as 05, even when transmitting a single tone, the tone signal can be transmitted without lowering the S / N ratio of the tone signal. Therefore, there is an advantage that a single tone signal can be reliably recognized even in an in-band ringer or the like.

Further, since the frequency shift unit 215 in the transmission unit 210 performs coordinate determination on a specific frequency when transmitting a tone signal, a single tone signal is always determined to have the same coordinates. Therefore, there is an advantage that the determination point does not move and the S / N ratio of the signal can be improved. Further, the receiving section 220 includes the frequency reverse shift section (frequency shift section, second frequency shift section) 222, so that the receiving side can perform the frequency reverse shift corresponding to the frequency shift performed on the transmitting side as the opposing device. By doing so, it becomes possible to reproduce a single tone signal from the transmitted DC signal without lowering the S / N ratio.

(B) Description of the Second Embodiment FIG. 11 is a block diagram of the transmitting section 2 of the modem according to the second embodiment of the present invention.
Although FIG. 10A is a diagram showing a modem as a communication device according to the second embodiment, it can be used as the modems 105 and 106 in the communication system as shown in FIG. 31, as in the first embodiment. it can.

Further, in the case of the second embodiment, basically the same as the receiving section 220 shown in the first embodiment can be used. Description is omitted. The transmitting unit 210A illustrated in FIG. 11 is different from the transmitting unit 210A210 according to the first embodiment in the following points. (1) The frequency shift can be changed according to the frequency of the tone signal used in the in-band ringer. (2) It is determined whether or not a tone signal is transmitted. (3) Output of frequency shift section 215A and coordinate determination section 21
The point that the phase difference with the output of the output 61 is obtained and the phase error is corrected based on the phase difference.

The frequency shift unit 215 shown in FIG.
In A, -1300Hz, -900Hz, -600H
Four kinds of frequency shifts of z and -300 Hz can be performed. Also in this case, it is assumed that the carrier signal in demodulation section 212 has a frequency of 1700 Hz. The frequency of the tone signal used in the in-band ringer is not limited to 3000 Hz as in the first embodiment, but may be other frequencies such as 2600 Hz, 2300 Hz, and 2000 Hz. When the in-band ringer supports the four types of tone signals, only -1300 Hz is not enough as a frequency shift amount to convert the tone signal into a DC signal.
It is necessary to be able to set frequency shift amounts such as z, -600 Hz, and -300 Hz.

In this case, the same frequency shift carriers as those of the above four types of frequencies can be selectively used as the frequency shift carriers used in frequency shift section 215A shown in FIG. 11 (equivalent circuit). Is almost the same as FIG. 6). Here, if the tone signal used in the in-band ringer should have a specific frequency for each system, the frequency shift carrier used in the frequency shift unit 215A is fixedly set. Just do it. If the frequency of the tone signal used is assumed to change in some cases, the frequency of the frequency shift carrier may be appropriately selected according to the transmitted tone signal.

The frequency shift carrier used in the frequency shift section 215A can be set according to the single frequency of the tone signal included in the input analog signal. That is, in the frequency shift unit 215A, for example, as shown in FIG.
Carrier information of the real part component and the imaginary part component according to the frequency shift carrier (cos θ _{1 to} cos θ ₄ , sin θ _{1 to} sin
θ ₄ ) is stored in the table 215A-1. When any one of the above-mentioned four types of frequency shift carriers is selected, 2 is used as selection information from outside.
The digital information of bits is input, and the carrier information can be extracted by referring to the above-mentioned table 215A-1 based on the selection information.

As described above, by allowing the frequency shift unit 215A to cope with a plurality of types of frequency shifts, even when tone signals having different frequencies are used for the in-band ringer, each tone signal can be used. It can be converted to a DC signal and transmitted via a dedicated line so that the S / N ratio does not decrease. It is needless to say that the received signal cannot be correctly reproduced unless the amount of frequency reverse shift in receiving section 220 is set to an amount corresponding to the amount of frequency shift in transmitting section 210A.

When the frequency shift amount in transmitting section 210A is fixedly set, the frequency reverse shift amount in receiving section 220 may be set in advance so as to be fixed. Here, a frequency deviation may occur in the single tone signal input to the transmission unit 210A, or a deviation may occur in a clock signal serving as a reference for signal processing in the modem. When there are such various deviations, the frequency shift unit 21
The single tone signal frequency-shifted by 5A may not be a complete DC signal. If the frequency-shifted signal is not a complete DC signal, a decision error will appear in the decision result on the two-dimensional plane, but since this decision error accumulates over time and increases, it should originally be a single decision point. There is a possibility that the signal point corresponding to the single tone signal to be fixed moves to another determination point.

In the second embodiment, when a single tone signal is transmitted and received, it is assumed that a single decision point is transmitted and received. In such a case, the received signal may not be recognized as a tone signal. The above (2) and (3) are configurations used to solve such a problem.

As a configuration for this purpose, the transmission unit 210A according to the second embodiment includes the transmission unit 21A according to the first embodiment.
In addition to 0A, a judgment point judgment unit 2163 and a phase error detection unit 2165 and a phase error correction unit 2166 are provided.
Further, the transmission unit 210A according to the second embodiment additionally includes first and second normalization units 2162 and 2164.
FIG. 12 shows a determination point determination unit 2163 (determination 1 in the figure), a first normalization unit 2162 (normalization in the figure), and a phase error detection unit 216.
5 and an equivalent circuit of the phase error correction unit 2166.

Note that the coordinate judging section 2161 uses the first
This is the same as that in the embodiment (see reference numeral 216). The determination point determination unit 2163 determines whether or not the input signal is a single tone signal. The phase error detection unit 2165 determines the phase of the signal output from the frequency shift unit 215A and the coordinate determination. The phase difference (phase error) from the phase of the signal output from the unit 2161 is detected. Further, phase error correction section 2166 corrects the phase error of the signal output from frequency shift section 215A based on the phase error detected by phase error correction section 2166.

As described above, when the coordinate determination of a single tone signal is performed, the result of the determination should be the same determination point. On the other hand, in the case of other voice / fax signals, since various frequency components are included,
Even if the frequency shift is performed, it can be considered that the possibility that the same determination point is continuously output from the coordinate determination unit 2161 is extremely low.

That is, the judgment point judgment unit 2163 receives the coordinate judgment result from the coordinate judgment unit 2161 and determines whether or not the input signal is a single tone signal based on whether or not the same judgment result is input. Is determined.
Specifically, the determination point determination unit 2163 includes the coordinate determination unit 2
The decision point of the signal (DECOUT) output from the output signal 161 is confirmed, and if the same decision point continues for a predetermined number (15 symbols in the case of the second embodiment), the input signal becomes a single tone signal. It is determined that they correspond (in the figure). On the other hand, when consecutive judgment points are not the same judgment point,
The judgment point judgment unit 2163 judges that this signal is not a single tone (in the figure).

If the input signal corresponds to a single tone signal, the determination point coordinates are normalized, the phase error between the output of the frequency shift unit 215A and the output of the coordinate determination unit 2161 is detected, and the output of the frequency shift unit 215A is output. Phase error correction is performed. It should be noted that the phase error detection is performed once in the case of the second embodiment when the same determination points of 15 symbols continue.

When the same judgment point of 15 symbols is detected, the output from the judgment point judgment section 2163 (the same as the output of the coordinate judgment section 2161) is multiplied by the first normalization section 2162 by a coefficient 1 / r. The coordinates are normalized. Subsequently, the signal normalized by the first normalization unit 2162 is output to the phase error detection unit 2165. Note that the input to the phase error detection unit 2165 shown in FIG. 12 is divided into a real part and an imaginary part. The signal before being input to the phase error detection unit 2165 is a vector signal (represented by a double line in the figure).

On the other hand, the signal output from frequency shift section 215A is input to second normalization section 2164, where the signal is normalized. FIG. 13 shows an equivalent circuit of the second normalization unit 2164. As shown in FIG. 13, the second normalization unit 2164 includes a reciprocal operation unit 21641,
It is configured to include a multiplying unit 21624 and a rounding unit 21643.

FIG. 13 also shows a state where the signal is divided into a real part and an imaginary part. Second normalization unit 2164
Is input to the reciprocal operation unit 21641,
The reciprocal is calculated. Subsequently, the second normalization unit 2164
Is multiplied by the output from the reciprocal operation unit 21641 by the multiplication unit 21624 and the rounding processing unit 2164
By performing the rounding process at 3, the output signal from the frequency shift unit 215A is normalized.

When the decision point decision unit 2163 determines that the same decision result is continuous, the phase error detection unit 2165 determines the phase of the signal subjected to the frequency shift by the frequency shift unit 215A and the coordinate decision. It detects a phase difference from the phase of the signal from the unit 2161 and has a function as a phase difference detection unit. Specifically, the second normalization unit 21
64, the normalized outputs NRRFR and NRRFI are input. Then, a phase error between the output of the first normalization unit 2162 and the output of the first normalization unit 2162 is detected by the phase error detection unit 2165.

Subsequently, a signal indicating the detected phase error is input to a phase error correction unit 2166. The phase error correction unit 2166 uses the phase difference detected by the phase error detection unit 2165 to make the frequency shift unit 215A
And corrects the phase of the frequency-shifted signal and outputs the corrected signal to the coordinate determination unit 2161, which has a function as a phase correction unit.

More specifically, in phase error correction section 2166, outputs RRFR ', RFR from frequency shift section 215A are output.
RFI ′ is input, the phase error is corrected based on the output from the phase error detection unit 2165, and RRFR, RFR
Output as RFI. On the other hand, the judgment point judgment unit 2163
Is determined not to be a single tone, the phase error correction is not performed. In other words, in the case of a signal such as a normal voice, there is a difference in phase and amplitude between the preceding and succeeding symbols, which can be considered as a matter of course. Therefore, in the case of such a signal, it is not necessary to perform the phase error correction. Because there is no. Specifically, the process for not performing the phase error correction is controlled so that the phase error output from the phase error detection unit 2165 is 0 °, that is, there is no phase error.

If the same determination point is not continuous for 15 symbols but is the same as the determination point one symbol before, coordinate normalization and phase error detection of the determination point are not performed, but the phase error Correction is performed (see FIG. 12). By adopting such a configuration, when a single tone is transmitted, it is possible to prevent the movement of the determination point based on the deviation of the tone signal or the clock signal, and the like. Is not a tone signal, such phase error correction may not be performed.

The receiving side does not need to perform processing such as phase error detection and correction according to the type of the received signal. In other words, since the decision point to be received corresponds to the decision point to be transmitted, if the decision point does not move on the transmitting side, the decision point does not move in the received signal. As described above, according to the second embodiment of the present invention, when the single-tone signal is transmitted by providing the decision point determination unit 2163 and the phase error detection unit 2165 and the phase error correction unit 2166, the tone In order to prevent the movement of the decision point due to the deviation of the signal or the like, a phase difference between the phase of the frequency-shifted signal and the phase of the determined signal is obtained, and the frequency is shifted. The phase error of the signal can be corrected, and the movement of the determination point when a single tone signal is transmitted can be prevented.

In particular, when a single tone signal is transmitted, it is necessary to prevent the decision point from moving. However, it is necessary to prevent the signal from changing its phase even when a frequency shift is performed as in a normal voice. On the other hand, since it is not necessary to take measures to prevent the movement of the decision point, by performing the phase error correction only while the single tone signal is being transmitted,
It becomes unnecessary to perform unnecessary phase error correction.

Here, whether or not the signal is a single tone signal is determined by
By making use of the fact that the DC-converted tone signal is arranged at the same point, but in the case of an audio signal or the like, the same judgment point is not continuous, a single tone signal is transmitted in a simple manner. Can be determined. Also, since the frequency shift amount in the frequency shift unit 215A can be set according to the single frequency of the tone signal included in the input analog signal, tone signals having different frequencies can be used for the in-band ringer. In this case, each tone signal can be converted to a DC signal and transmitted via a dedicated line so that the S / N ratio does not decrease.
There is an advantage that the received signal can be correctly reproduced.

(C1) Description of Third Embodiment FIG. 15 is a block diagram showing a modem signal transmitting section (transmitting section, transmitting apparatus) constituting a communication apparatus according to a third embodiment of the present invention, and FIG. FIG. 11 is a block diagram illustrating a modem signal receiving unit (receiving unit, receiving device) included in a communication device according to a third embodiment of the present invention.

The modem as the communication device according to the third embodiment can also be used as the modems 105 and 106 in the communication system as shown in FIG. That is, if the modem according to the third embodiment is applied as, for example, the modem 105 (located at the position of the modem 105), the modem 101 and the terminals 101 and 102 accommodated in the private branch exchange 103 by the modem signal transmitting unit 40 shown in FIG. The transmission analog signal of the
, While the modem signal receiving unit 50 shown in FIG.
9, 110 for analog signals.

Further, in the modem signal transmitting section 40,
The single tone from the in-band ringer 104 can be demodulated, judged, etc., and transmitted. The modem signal receiving unit 50 decodes the single tone (judgment data) from the in-band ringer 107. ,
Modulation processing or the like can be performed and output to the in-band ringer 104.

As described above, the modem according to the third embodiment has the modem signal transmitting section 40 shown in FIG. 15 and the modem signal receiving section 50 shown in FIG. 16 in detail. . Although the configuration of the modem according to the third embodiment is also described in detail focusing on the case where it is arranged at the position of the modem 105 shown in FIG. 31, the opposite modem 106 has the same configuration as the modem 105. It has a configuration.

Here, the modem signal transmitting section 40 performs A / D
Conversion section 41, demodulation section 42, carrier generation section 43, roll-off filter 44, gain control section 45, phase difference calculation section 4
6, a single tone determination unit 47, a determination unit 48, and a modem transmission processing unit 49. A / D converter 4
1 receives an analog signal (for example, a voice band of 0.3 to 3.4 kHz) input from the telephone terminal 102, the FAX terminal 101 or the in-band ringer 104, and converts it into a digital signal at a sample rate of, for example, about 10 to 11 kHz. Things.

The demodulation section 42 gives angle information having a carrier frequency of, for example, about 1700 Hz generated by the carrier generation section 43 to the digital data from the A / D conversion section 41 for each predetermined angle. The signal is demodulated into a baseband signal. Further, the roll-off filter 44 performs a decimation process on the demodulated signal from the demodulation unit 114 to obtain a sample rate (about 10 to 11 kHz, 4 samples / symbol).
Through conversion to a symbol rate (for example, about 2500 to 2750 Hz, 1 sample / symbol)
It reduces the amount of information and has a function as a filter for decimation processing.

Note that the 1700 Hz frequency band generated by the above-described carrier generation unit 43 and the symbol rates 2500 to 275 converted by the roll-off filter 44 are used.
The frequency band of 0 Hz corresponds to the voice and recommendation 29, V.S. 22
bis and V.I. It can be commonly used in consideration of the frequency band set at 32 or the like. In particular, the demodulation frequency band of 1700 Hz is described in Recommendation V.7. G3FA at 29
This corresponds to the carrier frequency of X.

At the stage before the operation in phase difference calculating section 46, gain control section 45 performs roll-off filter 44 based on maximum level information of the demodulated signal inputted a predetermined number of times continuously in symbol units. It performs gain control on the demodulated signal (transmission data) output from, and has a configuration as shown in FIG. 17 in detail.

That is, as shown in FIG. 17, the gain control unit 45 includes a vector length calculation unit 45a, a maximum value determination unit 45b,
It comprises a gain ratio calculation unit 45c, a gain control data determination unit 45d, a table 45e, a delay unit 45f, and a multiplication unit 45g. Here, the vector length component calculation unit 45
a calculates the vector length component by adding the square operation values of the real component (R) and the imaginary component (I) to the output signal (vector information) from the roll-off filter 44, Multiplying units 45a-1, 45a
-2 and an adder 45a-3.

The maximum value judging section 45b judges and selects the vector length information having the maximum value from the vector length information inputted continuously for 15 symbols.
The gain ratio calculation unit 45c includes the vector length information (the sum of squares calculation value; for example, “1”) of the maximum value information of the determination surface used in the determination unit 48 at the subsequent stage from the maximum value determination unit 45b. Calculates the ratio to the sum of squares.

Further, the gain control data determining unit 45d
Based on the ratio of the vector length information calculated by the gain ratio calculator 45c, for example, a table 45e as shown in FIG.
To extract the gain information on which the automatic gain control is to be performed. The gain information extracted by the gain control data determination unit 45d is used for automatic gain control for every 15 symbols in the subsequent multiplication unit 45g, and as gain information for every 15 symbols,
It is sent to the receiving side together with other transmission data.

The delay unit 45f outputs the maximum value judgment unit 45 for the output signal from the roll-off filter 44.
The data of 15 symbols for which the maximum value of the vector length is selected in b is output with a delay. Further, the multiplication unit 45g multiplies the data delayed by 15 symbols by the delay unit 45f by a gain based on the automatic gain control information from the gain information data determination unit 45d. Can be gain-controlled on the basis of the maximum value of the determination surface in the determination unit 48.

Incidentally, the phase difference calculating section 4 shown in FIG.
Numeral 6 is for calculating a phase difference between successive demodulated signals from the demodulation unit 42. Specifically, the data gain-controlled by the above-described gain control unit 45 is continuously input at a symbol rate, and a phase difference is calculated for data between adjacent symbols. Note that, as shown in FIG. 19, for example, as shown in FIG. 19, a level normalizer 46-1 is provided at the preceding stage of the phase difference calculator 46, and data that is continuously input and whose level is adjusted as necessary is used. Thus, the phase difference can be calculated (see FIG. 15).
Not shown).

That is, the phase difference calculating section 4 shown in FIG.
In the previous stage of No. 6, the data of the input real component and imaginary component (RRF
R, RRFI) is provided with a level normalizing section 46-1 for normalizing the maximum value level to “1”. Here, the normalizing unit 46-1 includes a reciprocal operation circuit 68 that calculates the reciprocal of the amplitude r in the real component and the imaginary component, and multiplies the real component and the imaginary component by the reciprocal 1 / r of the amplitude. Parts 61a and 61b are provided. In the reciprocal operation circuit 68, 62a and 62b are square operation units,
63 is an adder, 64 is a multiplier, 65 is an adder, 66 is a square operation unit, and 67 is an adder.

Further, the phase difference calculating section 46 calculates the real component (cos a) and the imaginary component (sin a) of which the maximum level has been normalized by the level normalizing section 46-1, respectively. The difference from (cos b, sin b) is calculated and output. That is, the phase difference [cos (a−
b)] is output as a real component (RRFR), while the phase difference [sin (ab)] is output as an imaginary component (RRFI).

It should be noted that in the phase difference calculating section 46, 69
a and 69b are delay units; 70a and 70b are multiplication units;
a and 71b are adders, 72a and 72b are multipliers, 73
Reference numerals a and 73b denote rounding units. That is, in the above-mentioned phase difference calculating section 46, the following equations (3) and
An operation as shown in (4) is performed.

Cos (ab) = cos a · cos b + sin a · sin b (3) sin (ab) = sin a · cos b−cos a · sin b (4) By the way, the gain control section 45 (or roll-off filter 4)
The phase of the data output from 4) is, for example, signals (A1) to (A) shown in FIG.
As shown in 3), the signal is input with a constant phase difference θ for each symbol, and the level (amplitude) of the signal input for each symbol always takes a constant value.

Therefore, as shown in FIG. 21, the phase difference calculator 46 calculates the phase difference between adjacent symbols for the tone signal as demodulated data input at the symbol rate from the gain controller 45. Can always be output as one point of data [phase difference signal, see (A4)]. Further, a single tone determination unit 47 as a transmission side single tone determination unit determines whether or not the demodulated signal demodulated by the demodulation unit 42 is a single tone. As a result of this determination, When the demodulated signal is not a single tone, the demodulated signal from the demodulation unit 42 is output to the subsequent determination unit 48. When the demodulated signal is a single tone, the phase difference signal from the phase difference calculation unit 46 is output. Is output to the determination unit 48 at the subsequent stage.

More specifically, the single tone determination section 47
Is obtained when the level of the demodulated signal continuously inputted a predetermined number of times (for example, 15 times) from the gain control unit 45 is constant.
The fifteen consecutive demodulated signals are determined to be a single tone, and based on the result of the determination, a signal to be output to the subsequent determination unit 48 is selected as described above. It is becoming.

The determination section (coordinate determination section) 48 receives the signal subjected to the decimation processing by the roll-off filter 44 and determines the coordinates on a two-dimensional plane. A determination surface 48 having 63 determination points with a radius (maximum value) of “1” as shown in FIG.
A. Specifically, the coordinate determination is performed on either the demodulated signal from the demodulation unit 42 (the signal from the gain control unit 45) or the phase difference signal from the phase difference calculation unit 46. The signal demodulated into a signal has a necessary information amount to be transmitted on the dedicated line 111.

That is, in the determination section 48, if the result of the determination in the single tone determination section 47 is that the demodulated signal is not a single tone, coordinate determination is performed on the demodulated signal from the demodulation section 42 while the demodulated signal is If it is a tone, the phase difference signal from the phase difference calculation unit 46 [(A
4)] is determined.

Thus, when the demodulated signal is a single tone, determination section 48 can perform coordinate determination on the phase difference signal [see (A4) in FIG. 21] from phase difference calculation section 46. Therefore, the determination result can always be stabilized at a single point value (see point (P1) in FIG. 22). Thereby, the resolution of the single tone is increased, and the determination error in the determination unit 48 is reduced.

Further, the modem transmission processing section 49 applies, for example, gray / natural conversion, summation, signal point generation, roll-off filter processing, modulation processing, D / A conversion to the digital data as a determination result from the determination section 48. Modem processing such as processing, and the modem signal (analog signal) subjected to such modem processing is transmitted to the dedicated line 1
The signal is transmitted to the opposing modem 106 (or the in-band ringer 107) via the interface 11 and has a function as a signal transmitting unit that transmits the determination result of the determining unit 48.

The components 42 to 49 of the modem signal transmitting unit 40 except for the A / D converter 41 are mainly composed of a DSP (Digital Signal Processor) and an MPU (Micr
oprocessor Unit). FIG.
The modem signal receiving unit 50 shown in FIG.
1, a coordinate decoding unit 52, a phase sum calculation unit 53, a single tone determination unit 54, a gain control unit 55, a roll-off filter 56, a modulation unit 57, a carrier generation unit 58, and a D / A conversion unit 59 Have been.

That is, the modem reception processing section 51 performs A / D conversion processing, demodulation processing, roll-off filter processing, and automatic reception on a signal received from the opposite modem 106 (or in-band ringer 107) via the dedicated line 111. It performs inverse modem processing such as gain control, automatic equalization, carrier phase correction, signal point determination, and difference.
Has a function as a signal receiving unit that receives a transmission signal from the communication line via the line 111.

The coordinate decoding section 52 decodes continuous reception signals (judgment data) subjected to inverse modem processing by the modem reception processing section 51. In other words, the coordinate decoding unit 52 decodes the determination data determined by the modem signal transmitting unit of the facing modem 106 into vector information having coordinate information.

The phase sum calculation unit 53 includes a coordinate decoding unit 5
In the received signal decoded into vector information in step 2, the sum of successive received signals is calculated. That is, this phase sum calculation unit 53 is
If the reception signal transmitted from the modem and received through the modem reception processing unit 51 and the coordinate decoding unit 52 is the determination information of the phase difference information, the phase sum calculation unit 53 performs the phase sum calculation. Thus, the original data before the difference calculation can be reproduced.

Further, the single tone determining section 54 as the receiving side single tone determining section, based on gain control information from the opposite modem 106 (gain information determined by the gain control data determining section 45d). This is for determining whether or not the level of the received signal input continuously for a predetermined number of times is constant. When the level is constant, the received signal input continuously for a predetermined number of times is a single tone. Is determined.

Here, if the received signal is not a single tone based on the determination result in single tone determination section 54, the received signal from coordinate decoding section 52 is converted to gain control section 5
5, when the received signal is determined to be a single tone, the phase sum signal from the phase sum calculation unit 53 is output to the gain control unit 55. Based on gain control information from the opposing modem 106 (gain information determined by the gain control data determination unit 45d), the gain control unit 55 calculates a received signal (vector information) from the single tone determination unit 54 based on: The amplitude is converted into the original amplitude before gain control in the gain control unit (see reference numeral 45) on the transmission side.

Further, the roll-off filter 56 controls the signal on which the gain control has been
It has a function as an interpolation processing filter that performs interpolation processing (processing corresponding to the above-described decimation processing in the loaf-off filter 116 on the transmission side). In other words, the symbol rate (for example, 250
0-2750 Hz) to the sample rate (10-1
Through conversion to about 1 kHz, the amount of information can be restored.

The modulation section 57 modulates the output signal from the roll-off filter 56 with a carrier frequency signal of about 1700 Hz generated by the carrier generation section 58, and converts the baseband signal into the original frequency band (for example, audio signal). The signal is a signal of 0.3 to 3.4 kHz). Therefore, if the received signal is not a single tone based on the result of the determination by the single tone determination section 54, the modulation section 57 modulates the received signal while determining that the received signal is a single tone. The modulation section 57 modulates the phase sum signal from the phase sum calculation section 53.

Further, the D / A converter 59 includes a modulator 57
Is converted into an analog signal, and the converted analog signal is output to the in-band ringer 104 as an output of the modem signal receiving unit 50. Each of the components 51 to 58 of the modem signal transmitting unit 50 except the D / A converting unit 59 is mainly configured by a DSP (Digital Signal Processor) and an MPU (Microprocessor Unit).

With the above-described configuration, the modem according to the third embodiment of the present invention is replaced with the modems 105 and 106 shown in FIG.
When applied as
When communication is performed between the FAX terminals 101 and 109, the dial information subjected to signal conversion by the in-band ringers 104 and 107 is transmitted to the private branch exchanges 103 and 1 respectively.
08, and analog signals such as voice signals and fax signals are exchanged via the modems 105 and 106 and the dedicated line 111.

For example, in the modem signal transmitting section 40 constituting the modem 105, the FAX
When transmitting a signal or transmission data as an analog signal from the telephone terminal 102 or the in-band ringer 104 to the dedicated line 111, each signal processing in the A / D converter 41, the demodulator 42, and the loaf-off filter 44 is performed. After that, the automatic gain control is performed in the gain control unit 45.

The gain information when performing automatic gain control in the gain control section 45 is transmitted once per 15 symbols (6 bits), for example, as shown in (B1) in FIG. ing. For example, while transmission data is transmitted at 3 kHz, gain information is transmitted at 200 Hz. Further, in the single tone determination section 47, the gain control section 45 outputs a predetermined number of times (for example, 15
Times) It is determined whether or not the transmission data is a single tone based on the constant level of the demodulated signal input continuously. That is, if the demodulated signal is at a constant level for 15 consecutive symbols, the transmission data is determined to be a single tone, and if the demodulated signal is not at a constant level continuously, a signal other than the single tone ( (For example, a signal such as a voice or a facsimile).

Here, in the determination section 48, when the single tone determination section 47 determines that the transmission data is a single tone, the phase difference in the continuous transmission data from the phase difference calculation section 46 is determined. In addition, when the transmission data is determined to be a signal other than a single tone, the coordinate determination is performed on the transmission data from the gain control unit 45.

As a result, for a single tone, the resolution required for recognition by the in-band ringer 107 can be maintained and transmitted without deterioration of S / N. That is, the signal returned to the baseband in the demodulation unit 42 has a constant signal level in the case of a single tone,
The single tone determination section 47 determines that the tone is a single tone if the certain level continues. In the phase difference calculation unit 46,
Data obtained by performing a phase difference between the current signal and the past signal (one tap before) has a constant phase in the case of a single tone. That is, if the determination unit 48 makes a determination on this phase difference signal, it stops at a single point on the determination surface, so that the determination result is always the same, and a pure tone can be transmitted.

Thereafter, the transmission digital data (for example, 1) whose coordinates have been determined by the determination section 48 as described above.
9.2 kbps ~), the modem transmission processing unit 49
After receiving the modem processing, the opposite (receiving) modem 106 (in-band ringer 107) via the dedicated line 111
Sent to Further, the receiving modem 106 receives a transmission signal from the modem 105 via the dedicated line 111. That is, after signal processing is performed in the modem reception processing unit 51 and the coordinate decoding unit 52, the phase sum calculation unit 53 calculates the phase sum of continuous reception data.

When receiving the transmission data from the opposite (transmission side) modem 105 as the reception data, the single tone determination section 54 checks the continuity of the reception data from the coordinate decoding section 52 at a certain level. It monitors and determines whether the received data is a single tone. In particular,
The single tone determination section 54 determines whether the received data is a single tone based on the gain information from the gain control data determination section 45d of the transmitting modem 105. That is,
If the received data is at a fixed level for 15 consecutive symbols, it is determined that the received data is a single tone. If not, a signal other than the single tone (for example, a facsimile signal, a voice signal)
Is determined.

As a result of the determination by the single tone determining section 54, when the received data is a single tone, the gain control and the loaf are performed on the calculation result of the phase sum in the continuous received data from the phase sum calculating section 53. After performing the off-filter processing, modulation is performed by the modulation unit 57. Further, if the received data is a signal other than a single tone (eg, voice,
In the case of a signal such as a facsimile signal, the modulator 57 modulates the data received from the coordinate decoder 52 after performing gain control and loaf-off filtering.

In other words, when it is determined that the received data is a single tone, the modulator 57 modulates the operation result of the phase sum and the received data is a signal other than the single tone. Is determined, the received data is modulated. Note that the received data (symbol rate) modulated as described above is converted to an analog signal (sample rate) by the D / A converter 59, and then output to the in-band ringer 107. The in-band ringer 107 can reliably recognize the pure tone signal transmitted by the determination data of the difference information as described above.

As described above, according to the modem according to the third embodiment of the present invention, in the modem signal transmitting section 40, the phase difference calculating section 46, the single tone determining section 47 and the determining section 4
8, when the received data is determined to be a single tone, the phase difference of the continuous received data is calculated, the coordinate determination is performed on the calculation result of the phase difference, and the coordinate is transmitted. If the transmission data is determined to be a signal other than a single tone,
While performing coordinate determination on transmission data and transmitting it,
By providing the modem signal receiving unit 50, when the received data is determined to be a single tone, the phase sum of the continuous received data is calculated, and the calculation result of the phase sum is modulated. When it is determined that the received data is a signal other than a single tone, the received data can be modulated, so that it is possible to transmit a pure tone signal that satisfies the required S / N ratio. There is an advantage that the tone signal can be surely recognized on the receiving side.

(C2) Description of Modification of Third Embodiment In the third embodiment described above, the modem signal transmitting unit 40
The single-tone determination unit 47 of the first embodiment and the single-tone determination unit 54 of the modem signal receiving unit 50 determine whether the transmission data or the reception data is a single tone based on the consistency of the input signal level. However, the present invention is not limited to this, and it can be determined that the transmission data or the reception data is a single tone based on the consistency of the phase difference information of the continuously input signals.

In this case, the modem signal transmitting section 4
24A can be configured as shown in FIG. 24, and the modem signal receiving section 50A can be configured as shown in FIG. 25. That is, the configuration of the single tone determining unit 47A is different from that of the third embodiment (see reference numeral 40) in the modem signal transmitting unit 40A, but the other configurations (reference numerals 41 to 46, 48, The same applies to 49). In FIG. 24, the same reference numerals as those in FIG. 15 indicate substantially the same parts.

Here, if the phase difference between the demodulated signals input continuously for a predetermined number of times (for example, 15 times) in symbol units is constant, the single tone determining section 47A is a single tone. On the other hand, if not, it is determined to be a signal other than a single tone (for example, a FAX signal, a voice signal). Specifically, the single tone determination unit 47A monitors the consistency of the phase difference from the phase difference calculation unit 46, and if the demodulated signal of 15 symbols has a constant phase difference continuously, It is determined that the signal is a signal, and the phase difference calculation information from the phase difference calculation unit 46 is output to the determination unit 48 (see FIG. 24). , Is determined to be a signal other than a single tone,
The demodulation signal is output to the determination unit 48 (see FIG. 24).

As a result, the judgment section 48 determines that the third
As in the case of the embodiment, as a result of the determination in the single tone determination section 47A, if the demodulated signal is not a single tone, coordinate determination is performed on the demodulated signal from the gain control section 45, while the demodulated signal is a single tone. In some cases, coordinate determination can be performed on the phase difference signal from the phase difference calculation unit 46.

Also, the modem signal receiving section 50A is the same as that in the third embodiment (see reference numeral 50).
Although the configuration of the single tone determination unit 54A is different from
The other configurations (reference numerals 51 to 53, 54 to 59) are the same. In FIG. 25, the same reference numerals as those in FIG. 16 indicate substantially the same parts. That is, when the phase difference between the received signals input continuously for a predetermined number of times (for example, 15 times) in symbol units from the coordinate decoding unit 52 is constant, the single tone determination unit 54A determines that the received signal is a single tone. While it is determined that there is, if not, it is determined to be a signal other than a single tone (for example, a FAX signal, a voice signal).

Specifically, the single tone determination section 54A
The phase difference of the received data from the coordinate decoding unit 52 is monitored for consistency, and when the received signal of 15 symbols has a constant phase difference continuously, it is determined that the received signal is a single tone signal.
While the phase sum calculation information from the phase sum calculation unit 53 is output to the gain control unit 55 (see FIG. 25), if the received signal of 15 symbols does not have a constant phase difference continuously, other than a single tone The signal is received from the coordinate decoding unit 52 and output to the gain control unit 55 (see FIG. 25).

Thus, based on the determination result in single tone determination section 54A, modulation section 57 modulates the reception signal from coordinate decoding section 52 while the received signal is not a single tone, based on the determination result in single tone determination section 54A. If it is determined that the tone is a single tone, the phase sum signal from the phase sum calculation unit 53 can be modulated. Therefore, also in the present modification, in the modem signal transmitting section 40A, the phase difference calculating section 46, the single tone determining section 47A, and the determining section 4
8 and the modem signal receiving section 50, a pure tone signal satisfying the required S / N ratio can be transmitted as in the case of the third embodiment. There is an advantage that the tone signal can be surely recognized on the receiving side.

(D1) Description of the Fourth Embodiment FIG. 26 is a block diagram showing a modem signal transmitting section constituting a modem according to a fourth embodiment of the present invention, and FIG. 27 is a block diagram showing a fourth embodiment of the present invention. FIG. 3 is a block diagram showing a modem signal receiving unit constituting the modem. The modem according to the fourth embodiment can also be used as the modems 105 and 106 in the communication system as shown in FIG.

That is, if the modem according to the fourth embodiment is applied to, for example, the modem 105 (located at the position of the modem 105), the terminal 101 accommodated in the private branch exchange 103 is transmitted by the modem signal transmitting section 79 shown in FIG. , 102
Is transmitted to the modem 106 via the dedicated line 111, and the analog signal from the terminals 109 and 110 on the opposite private branch exchange 108 side is received by the modem signal receiving unit 80 shown in FIG. be able to.

In the modem signal transmitting section 79,
The single tone from the in-band ringer 104 can be demodulated and determined before being transmitted, and the modem signal receiving unit 80 decodes and modulates the single tone (determination data) from the in-band ringer 107. Processing and the like can be performed and output to the in-band ringer 104.

As described above, the modem according to the fourth embodiment includes the modem signal transmitting section 79 shown in FIG. 26 and the modem signal receiving section 80 shown in FIG. 27, similarly to the third embodiment. It is configured. here,
The modem signal transmitting section 79 is different from the third embodiment (see reference numeral 40) in that the phase difference between successive data is irrespective of whether or not the input analog signal is a single tone. While performing the coordinate determination on the result of the above calculation, the modem signal receiving unit 80 calculates the phase sum for the continuously input received signal regardless of whether the received signal is a single tone or not. The difference is that modulation is performed on the result of the application.

In the following description, the case where the modem is applied as the modem 105 in the communication system shown in FIG.
It is needless to say that also has the same configuration as the modem 105. 26 and 27, the same reference numerals as those in FIGS. 15 and 16 indicate the same parts.

First, as shown in FIG. 26, a modem signal transmitting unit 79 according to the fourth embodiment includes an A / D converter 41, a demodulator 42, and a demodulator 42 similar to those in the third embodiment.
It includes a carrier generation unit 43, a roll-off filter 44, a gain control unit 45, a phase difference calculation unit 46, a determination unit 48, and a modem transmission processing unit 49, and includes a delay unit 75, a phase error detection unit 76, a feedback control unit 77, An error adding section 78 is provided.

In the case of the third embodiment (FIG. 19)
Similarly to FIG. 28, a level normalizing section 46-1 is provided in front of the phase difference calculating section 46, for example, as shown in FIG.
If necessary, a phase difference can be calculated for data that is continuously adjusted in level (not shown in FIG. 26). In FIG. 28, FIG.
The same reference numerals as 9 indicate similar parts.

Further, the phase error adding section 78 is interposed between the level normalizing section 46-1 and the phase difference calculating section 46, and feeds back and adds phase error information described later to the demodulated signal. , In detail, as shown in FIG. The phase difference calculator 46 calculates a phase difference between successive demodulated signals from the demodulator 42. That is, regarding the demodulated signal from the demodulation unit 42, whether the demodulated signal input through the processing in the roll-off filter 44, the gain control unit 45, the level normalization unit 46-1, and the phase error addition unit 78 is a single tone. Irrespective of whether or not, the phase difference between the demodulated signals that are continuously input is calculated and output to the determination unit 48.

More specifically, the phase difference calculating section 46 normalizes the maximum value level in the level normalizing section 46-1, and corrects the real component (co) in which the phase error has been corrected in the phase error adding section 78.
For s A) and the imaginary component (sin A), the difference between the data and the previously input data (cos B, sin B) is calculated and output. That is, the phase difference [cos (AB)] is output as the real component (RRFR), while the phase difference [sin (AB)
B)] as an imaginary component (RRFI).

Further, the judgment section (coordinate judgment section) 48 receives the signal (phase difference signal from the phase difference calculation section 46) subjected to the decimation processing by the roll-off filter 44, and coordinates the phase difference signal. This is to make a determination so that the signal demodulated into a baseband signal has a necessary information amount for transmission on the dedicated line 111. In this determination unit 48,
As in the case of the third embodiment described above, for example, it is possible to have a determination surface configured by determination points as shown in FIG.

The result of the judgment by the judgment section 48 is output after the modem transmission processing section 49 has been subjected to the modem processing in the same manner as in the third embodiment, and is output via the dedicated line 111. The data is transmitted to the opposite modem 106. Further, the phase error detection unit 76 detects a phase error based on the coordinate determination result from the determination unit 48 and the phase difference calculation result from the phase difference calculation unit 46 input via the delay unit 75. It is.

That is, the result of the phase difference calculation from the phase difference calculator 46 input to the phase error detector 76 is
5, the phase error can be detected by associating the data on which the phase difference has been calculated with the data on which the coordinate determination has been performed by the determination unit 48. Further, the phase error detection unit 76 performs a coordinate determination in the determination unit 48 on data obtained by calculating a phase difference of the signal (FAX signal, voice signal, etc.) other than a single tone by the phase difference calculation unit 46. This is for detecting a phase error generated as a result, and has a configuration as shown in FIG. 29 described later in detail.

Further, the feedback control unit 77 shown in FIG. 26 includes a single-tone determination unit (transmission-side single-tone determination unit) 47 having the same function as that of the third embodiment, and a data switching unit. 81. That is, the single tone determination unit 47 monitors the level of the demodulated signal input from the gain control unit 45 continuously for a predetermined number of times (for example, 15 times), and based on this constant, the demodulated signal input based on this level. Is a single tone or not, and the result of the determination is the data switching unit 8.
1 is notified.

More specifically, when the level of the demodulated signal input continuously from the gain control unit 45 for a predetermined number of times (for example, 15 times) is constant, the single tone determination unit 47
While it is determined that the demodulated signal input five consecutive times is a single tone, if the level of the demodulated signal input fifteen consecutive times is not constant, the demodulated signal is a signal other than the single tone. (FAX signal, voice signal, etc.), and notifies the data switching unit 81 of the determination result.

If the result of determination by single tone determination section 47 is that the demodulated signal from gain control section 45 is not a single tone, data switching section 81 performs phase error detection section 7.
6 to select the phase error detection information from the phase error adder 7
8 while the demodulated signal from the gain control unit 45 is a single tone, a signal (1
+ J0) is selected and output to the phase error adder 78.

In other words, under the control of the feedback control unit 77, when the single tone determination unit 47 determines that the demodulated signal is not a single tone, the phase error detected by the phase error detection unit 76 While the information is fed back to the phase difference calculator 46, if the demodulated signal is determined to be a single tone, the feedback of the phase error information detected by the phase error detector 76 to the phase difference calculator 46 is performed. To stop.

The above-described phase error detection section 76, feedback control section 77, and phase error addition section 78 have a configuration as shown in FIG. 29 in detail. Here, a level adjustment unit 76-1 including a coordinate decoding unit 82 and a multiplication unit 83 is provided at a stage preceding the phase error detection unit 76 as shown in FIG. You can do it.

That is, in the level adjusting section 76-1,
The determination output (DECOUT) continuously input as necessary is subjected to coordinate decoding processing by the coordinate decoding unit 82, and then the level is adjusted by the multiplication unit 83 (for example, “1 / 1.3” to the determination output). Can be used to detect the phase error (not shown in FIG. 26).

As shown in FIG. 29, the phase error detecting section 76 calculates the phase difference calculation result [real component cos (AB), imaginary component sin (AB)] from the phase difference calculating section 46. , The delay units 75 a and 7 constituting the delay unit 75 respectively.
5b and the judgment result from the judgment unit 48, and calculates the phase difference between the phase difference calculation result and the judgment result for each real component and imaginary component. .

The phase error detector 76 has multipliers 84a, 84b, adders 85a, 85a, and 84b basically similar to those in the phase difference calculator 46 (reference numerals 70a to 73b).
85b, multiplication units 85a and 85b, and rounding units 85a,
85b, and substantially performs the phase difference calculation substantially similar to the above-described equations (3) and (4).

The phase error adding section 78 receives the phase error detection information from the feedback control section 77 (1 + j0 when a single tone is input, and outputs the phase error detection section 76 when a non-single tone is input) to the level normalizing section. With respect to the demodulated signal (cos a, sin a) whose level has been adjusted in 46-1,
The addition is performed for each of the real component and the imaginary component, whereby the accumulation of the phase error generated by the determination in the determination unit 48 can be suppressed.

Further, as shown in detail in FIG. 29, the phase error adding section 78 includes multiplying sections 88a and 88b,
9a, 89b, multiplication units 90a, 90b and rounding processing unit 9
1a and 91b, and substantially performs a phase error addition operation as shown in the following equations (5) and (6). Note that “a” in each of the equations (5) and (6) is the phase information of the demodulated signal from the gain control unit 45,
“X” is the phase error detection information detected by the phase error detection unit 76.

Cos (a + X) = cos a · cos X−sin a · sin X (5) sin (a + X) = sin a · cos X + cos a · sin X (6) By the way, receiving the modem signal shown in FIG. The unit 80 includes a modem reception processing unit 51, a coordinate decoding unit 52, a phase sum calculation unit 53, a gain control unit 55, and a roll-off filter 5 similar to those in the third embodiment (see reference numeral 50).
6, a modulation section 57, a carrier generation section 58, and a D / A conversion section 59.
Does not have

That is, since the modem transmission processing section 79 of the transmitting modem 105 determines the coordinates of the one for which the phase difference has been calculated regardless of whether the tone is a single tone or not and transmits it, Modem reception processing unit 8
In the case of 0, it is not necessary to determine whether the received signal is a single tone or not, and the single tone determination unit 54 as in the third embodiment is omitted.

Therefore, in the modem signal receiving section 80 according to the fourth embodiment, regardless of whether or not the received signal is a single tone, the phase sum calculating section 53 performs the processing on the continuously input received signal. , The result of the calculation of the phase sum is interpolated by the roll-off filter 56, and then modulated by the modulation unit 57.

As in the third embodiment, the components of the modem signal transmitting unit 79 and the modem signal receiving unit 80 excluding the A / D converter 41 and the D / A converter 59 are mainly It comprises a DSP (Digital Signal Processor) and an MPU (Microprocessor Unit).
With the configuration described above, even when the modem according to the fourth embodiment of the present invention is applied as the modems 105 and 106 shown in FIG. 31, communication is performed between the telephone terminals 102 and 110 or between the facsimile terminals 101 and 109. At this time, the dial information subjected to the signal conversion by the in-band ringers 104 and 107 is transferred to the private branch exchanges 103 and 108.
An analog signal such as a voice signal or a facsimile signal is exchanged via the modems 105 and 106 and the dedicated line 111.

For example, in the modem signal transmitting unit 40 constituting the modem 105, the FAX
When transmitting a signal or transmission data as an analog signal from the telephone terminal 102 or the in-band ringer 104 to the dedicated line 111, each signal processing in the A / D converter 41, the demodulator 42, and the loaf-off filter 44 is performed. After that, the automatic gain control is performed in the gain control unit 45.

Here, the single tone determination section 47 of the feedback control section 77 determines whether or not the transmission data is a single tone when performing the coordinate determination on the transmission data and transmitting the data. Further, when the single tone determination unit 47 determines that the transmission data is a single tone, the phase difference calculation unit 46 does not receive the feedback of the phase error information from the feedback control unit 77. The phase difference between successive transmission data is calculated, and the calculation result of the phase difference is subjected to coordinate determination by the determination unit 48 and transmitted.

In other words, when it is determined that the transmission data is a single tone, the phase error of the transmission data preceding the phase difference calculation in the phase difference calculation unit 46 via the feedback control unit 77 is “ The signal (1 + j0) indicating "0" is added by the phase error adding unit 78, and the calculation result of the subsequent phase difference is determined by the determining unit 4
In step 8, the coordinates are determined and transmitted.

Further, when it is determined that the transmission data is a signal other than a single tone (for example, a voice signal or a facsimile signal), the phase difference calculator 46 calculates the phase difference between successive transmission data. The result of the phase difference calculation is subjected to coordinate determination and transmitted, while an error between the result of the phase difference calculation and the result of the coordinate determination is extracted by the phase error detection unit 76, and the feedback control unit 77 and the phase error addition unit 78 Then, when the phase difference is calculated for the next transmission data, the error is corrected.

In other words, when it is determined that the transmission data is not a single tone, the feedback control section 77 controls the phase difference calculation section 46 to add a phase error to the transmission data preceding the phase difference calculation section. Detector 7
6 is added by the phase error adding unit 78, and the calculation result of the phase difference is determined by the determining unit 4
In step 8, the coordinates are determined and transmitted.

Therefore, it is possible to suppress the accumulation of the phase error generated by determining the phase difference signal for the transmission data that is not a single tone by the feedback control. It should be noted that the transmission digital data (for example, 19.2 kbps or more) on which the determination has been made by the determination unit 48 as described above is transmitted to the modem transmission processing unit 49.
After receiving the modem processing, the opposite (receiving) modem 106 (in-band ringer 107) via the dedicated line 111
Sent to

Furthermore, the receiving modem 106 receives a transmission signal from the modem 105 via the dedicated line 111. That is, the modem reception processing unit 51 and the coordinate decoding unit 5
After the signal processing in 2 is performed, the phase sum calculation unit 53 calculates the phase sum of the continuous received data. That is, the modem transmission processing unit 79 of the transmission-side modem 105
In the above, since the coordinates are determined and transmitted with respect to the phase difference calculated irrespective of whether or not the received signal is a single tone, the received signal is also converted into the single tone in the modem reception processing unit 80 of the receiving modem 106. There is no need to determine whether or not there is.

Therefore, after performing the interpolation processing in the roll-off filter 56 on the calculation result of the phase sum in the phase sum calculation section 53,
Is modulated as it is. Note that the received data (symbol rate) modulated as described above is converted to an analog signal (sample rate) by the D / A converter 59, and then output to the in-band ringer 107. The in-band ringer 107 can reliably recognize the pure tone signal transmitted by the determination data of the difference information as described above.

As described above, according to the modem according to the fourth embodiment of the present invention, the demodulator 42, the phase difference calculator 46, and the determiner 48 are provided. In addition, it is possible to transmit a pure tone signal that satisfies a required S / N ratio and has an advantage that the tone signal can be reliably recognized on the receiving side.

Further, by providing the phase error detection section 76, the feedback control section 77 and the phase error addition section 78, when the single tone determination section 47 determines that the demodulated signal is not a single tone, Phase error detector 7
6 is fed back to the phase difference calculating section 46, and when the demodulated signal is determined to be a single tone, the phase error information detected by the phase error detecting section 76 is Since feedback to the phase difference calculation unit can be stopped, accumulation of a phase error generated by determining a phase difference signal for transmission data that is not a single tone can be suppressed by feedback control. Further, it is not necessary for the modem signal receiving section to determine a single tone, and the single tone, voice signal, and FAX signal can be communicated with little noise while simplifying the configuration of the modem signal receiving section. There are advantages.

(D2) Description of Modification of Fourth Embodiment In the above-described modem signal transmission section 79 in the fourth embodiment, the single tone determination section 47 of the feedback control section 79
In, based on the consistency of the input signal level,
It is determined whether the transmission data or the reception data is a single tone, but the present invention is not limited to this. Based on the consistency of the phase difference information of the continuously input signal, the transmission data is a single tone. It can also be determined that it is a tone.

In this case, the modem signal transmitting section 7
As shown in FIG. 30, 9A has a single tone determination unit 47A different from that of the above-described fourth embodiment (see reference numeral 79), but has other configurations (reference numerals 41 to 41).
46, 48, 49) are the same as those in the above-described fourth embodiment. In FIG. 30, the same reference numerals as those in FIG. 26 denote substantially the same parts.

Also in this case, as the modem signal receiving section, the same one as in the fourth embodiment (see reference numeral 80) can be used. Here, the single tone determination unit 47A performs the predetermined number of times (for example, 15
Times) When the phase difference between the demodulated signals input continuously is constant, the demodulated signal is determined to be a single tone,
Otherwise, a signal other than a single tone (eg, FA
X signal, audio signal).

More specifically, the single tone determination section 47A
The phase difference from the phase difference calculation unit 46 is monitored for consistency.
When the demodulated signals of five symbols have a constant phase difference continuously, it is determined that the signal is a single tone signal, and the fact is notified to the data switching unit 81. This allows
In the data switching unit 81, a signal (1+
j0) can be output to the phase error adder 78.

When the 15-symbol demodulated signal does not have a constant phase difference continuously, single-tone determining section 47A determines that the signal is a signal other than a single-tone signal, and notifies data switching section 81 to that effect. You are notified. Accordingly, the data switching unit 81 can select the phase error detection information from the phase error detection unit 76 and output the information to the phase error addition unit 78.

It is to be noted that the determination section 48 determines the phase difference calculation result from the phase difference calculation section 46 regardless of whether the demodulated signal is a single tone. By this means, a pure tone signal that satisfies the required S / N ratio can be transmitted for a single tone, but if the demodulated signal is not a single tone, the phase error detection unit 76 By feeding back the detected phase error at the time of the next phase difference calculation, it is possible to suppress accumulation of a phase error generated by determining a phase difference signal for transmission data that is not a single tone. is there.

Therefore, also in this modification, the demodulation section 42 and the phase difference calculation section 4 in the modem signal transmission section 79A.
6, a determination unit 48 and a phase error detection unit 7
6, feedback control unit 77A and phase error adding unit 7
8, it is possible to transmit a pure tone signal that satisfies the required S / N ratio, as in the case of the third embodiment, and the tone signal is reliably transmitted to the receiving side. There are advantages that can be made recognizable. Further, accumulation of a phase error generated by determining a phase difference signal for transmission data that is not a single tone can be suppressed by feedback control, and a single tone determination is performed in a modem signal receiving unit. This eliminates the necessity and has the advantage that a single tone, a voice signal, and a FAX signal can be communicated with little noise while simplifying the configuration of the modem signal receiving unit.

(E) Others In each of the above-described embodiments, the case where the present invention is applied to a modem as a communication device having a transmitting unit and a receiving unit has been described in detail.
0, 40A, 79, 79A or receiving units 50, 50A, 8
0,80A can be applied simply as a transmitting device or a receiving device.

Further, in each of the above-described embodiments, the case where the modem of the present invention is applied to the modems 105 and 106 connected via the dedicated line 111 has been described in detail. It can be applied to other lines that transmit and receive data.

[0193]

As described in detail above, claims 1, 3, 1
According to the fifth aspect of the present invention, since the transmitting device (transmitting unit) is provided with the frequency shift unit (first frequency shift unit) and the coordinate determining unit, even when a single tone is transmitted using a modem, the tone is not changed. A tone signal can be transmitted without lowering the S / N ratio of the signal. Therefore, there is an advantage that a single tone signal can be reliably recognized even in an in-band ringer or the like.

In addition, since the frequency shift unit (first frequency shift unit) in the transmitting apparatus (transmitter) determines the coordinates on a specific frequency when transmitting the tone signal, the single tone signal is Since the determination is always made at the same coordinates, there is an advantage that the determination point does not move and the S / N ratio of the signal can be improved.

[0195] Further, according to the present invention according to claim 2, 17, judging point determination unit, by which includes a phase difference detecting unit and the phase correcting unit, when sending a single tone signal, tone signal The difference between the phase of the frequency-shifted signal and the phase of the determined signal is calculated in order to prevent the movement of the determination point due to the deviation of the signal. Can be corrected, and the shift of the decision point when a single tone signal is transmitted can be prevented.

In particular, when a single tone signal is transmitted, it is necessary to prevent the decision point from being moved. However, it is necessary to prevent the signal from changing its phase even when a frequency shift is performed as in a normal voice. On the other hand, since it is not necessary to take measures to prevent the movement of the decision point, by performing the phase error correction only while the single tone signal is being transmitted,
It becomes unnecessary to perform unnecessary phase error correction.

Here, it is determined whether or not the signal is a single tone signal.
By making use of the fact that the DC-converted tone signal is arranged at the same point, but in the case of an audio signal or the like, the same judgment point is not continuous, a single tone signal is transmitted in a simple manner. Can be determined. According to the fourth aspect of the present invention, the frequency shift amount in the frequency shift unit can be set in accordance with the single frequency of the tone signal included in the input analog signal. Even when tone signals having the following are used for the in-band ringer, each tone signal can be converted to a DC signal and transmitted via a dedicated line so that the S / N ratio does not decrease. This has the advantage that the received signal can be correctly reproduced.

[0198] Further, according to the present invention of claim 10, 15, 16, wherein, by providing the frequency shift portion (second frequency shift unit) to the receiver (receiver), carried out on the transmitting side at the receiving side By performing the frequency reverse shift corresponding to the obtained frequency shift, a single tone signal can be reproduced from the transmitted DC signal without lowering the S / N ratio.

The present invention (Claims 5 to 9, 11 to 1)
4 , 18 to 22 ), the transmitting section (transmitting apparatus) includes the phase difference calculating section, the transmitting-side single tone determining section and the coordinate determining section, so that the demodulated signal is determined to be a single tone. and the case is to be inputted continuous to
Calculates the phase difference between the two signals , performs the coordinate determination on the calculation result of the phase difference, transmits the signal, and demodulates the signal.
When it is determined that the signal is a signal other than a single tone, the demodulated signal is subjected to coordinate determination and transmitted, while the receiving unit (receiving device) includes a receiving-side single-tone determining unit. In the case where the received data is determined to be a single tone, the phase sum of the continuous received data is calculated, the result of the phase sum calculation is modulated, and the received data is a signal other than the single tone. If it is determined that there is, the received data can be modulated, so that a pure tone signal that satisfies the required S / N ratio can be transmitted, and the tone signal can be reliably transmitted to the receiving side. There are advantages that can be made recognizable.

[0200] Further, Claim 6, according to the present invention described 19,21, at the transmission side single tone determination unit, when the demodulated signal is determined not to be a single tone in the phase error detection unit While the detected phase error information is fed back to the phase difference calculation unit, if the demodulated signal is determined to be a single tone, the phase error information detected by the phase error detection unit is sent to the phase difference calculation unit. , The accumulation of the phase error generated by determining the phase difference signal for the transmission data that is not a single tone can be suppressed by the feedback control.

[0202] Further, according to the present invention of claim 19, it is possible to omit the determination of a single tone in the modem signal receiver, a single tone or voice while simplifying the configuration of the modem signal receiver There is an advantage that signals and FAX signals can be communicated with little noise.

[Brief description of the drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a principle block diagram of the present invention.

FIG. 3 is a principle block diagram of the present invention.

FIG. 4 is a block diagram showing a transmitting unit of the modem according to the first embodiment of the present invention.

FIG. 5 is a block diagram showing a receiving unit of the modem according to the first embodiment of the present invention.

FIG. 6 is a diagram illustrating an equivalent circuit of a frequency shift unit according to the first embodiment of the present invention.

FIG. 7 is a diagram showing a single tone signal output from a roll-off filter according to the first embodiment of the present invention.

FIG. 8 is a diagram illustrating a single-tone signal after being frequency-shifted according to the first embodiment of the present invention.

FIG. 9 is a diagram showing a single tone signal whose coordinates are determined according to the first embodiment of the present invention.

FIG. 10 is a diagram illustrating a determination surface of a determination unit according to the first embodiment of the present invention.

FIG. 11 is a block diagram illustrating a transmitting unit of a modem according to a second embodiment of the present invention.

FIG. 12 is a block diagram illustrating a main part of a transmission unit of a modem according to a second embodiment of the present invention.

FIG. 13 is a diagram illustrating an equivalent circuit of a second normalization unit according to the second embodiment of the present invention.

FIG. 14 is a diagram showing a table for storing frequency shift carriers according to a frequency shift amount according to the second embodiment of the present invention.

FIG. 15 is a block diagram showing a modem signal transmission unit constituting a modem according to a third embodiment of the present invention.

FIG. 16 is a block diagram showing a modem signal receiving unit constituting a modem according to a third embodiment of the present invention.

FIG. 17 is a block diagram illustrating a main part of a modem signal transmitting unit according to a third embodiment of the present invention.

FIG. 18 is a diagram illustrating a main part of a modem signal transmitting unit according to a third embodiment of the present invention.

FIG. 19 is a block diagram illustrating a main part of a modem signal transmitting unit according to a third embodiment of the present invention.

FIG. 20 is a diagram for explaining an operation of a modem signal transmitting unit according to the third embodiment of the present invention.

FIG. 21 is a diagram for explaining an operation of a modem signal transmitting unit according to the third embodiment of the present invention.

FIG. 22 is a diagram for explaining an operation of a modem signal transmitting unit according to the third embodiment of the present invention.

FIG. 23 is a diagram for explaining an operation of the modem according to the third embodiment of the present invention.

FIG. 24 is a block diagram showing a modem signal transmission unit constituting a modem according to a modification of the third embodiment of the present invention.

FIG. 25 is a block diagram showing a modem signal receiving unit constituting a modem according to a modification of the third embodiment of the present invention.

FIG. 26 is a block diagram showing a modem signal transmission unit constituting a modem according to a fourth embodiment of the present invention.

FIG. 27 is a block diagram showing a modem signal receiving unit constituting a modem according to a fourth embodiment of the present invention.

FIG. 28 is a block diagram illustrating a main part of a modem signal transmitting unit according to a fourth embodiment of the present invention.

FIG. 29 is a block diagram illustrating a main part of a modem signal transmitting unit according to a fourth embodiment of the present invention.

FIG. 30 is a block diagram showing a modem signal transmission unit constituting a modem according to a modification of the fourth embodiment of the present invention.

FIG. 31 is a block diagram illustrating a communication system that performs communication via a dedicated line.

FIG. 32 is a block diagram illustrating a modem signal transmission unit.

FIG. 33 is a block diagram showing a modem signal receiving unit.

[Explanation of symbols]

Reference Signs List 2 demodulation unit 3 phase difference calculation unit 4 transmission-side single tone determination unit 5 coordinate determination unit 6 signal transmission unit 8 signal reception unit 9 phase sum calculation unit 10 reception-side single tone determination unit 11 modulation unit 12 communication device 13 transmission Unit (transmitting device) 14 receiving unit (receiving device) 15 opposing device 16 receiving unit 17 transmitting unit 18, 19 line 20 communication device 21 transmitting unit (transmitting device) 22 receiving unit (receiving device) 23 demodulating unit 24 phase difference calculation Unit 25 coordinate determination unit 26 phase error detection unit 27 single-tone determination unit on the transmission side 28 signal transmission unit 29 signal reception unit 30 phase sum calculation unit 31 modulation unit 33 facing device 34 reception unit 35 transmission unit 40, 40A modem signal Transmitter (transmitter, transmitter) 41 A / D converter 42 Demodulator 43 Carrier generator 44 Roll-off filter 45 Gain controller 45a Vector Length calculation unit 45b Maximum value determination unit 45c Gain ratio calculation unit 45d Gain control data determination unit 45e Table 45f Delay unit 45g Multiplication unit 46 Phase difference calculation unit 46-1 Level normalization unit 47, 47A Single tone determination unit (transmission side) Single tone determination unit) 48 determination unit (coordinate determination unit) 48A determination surface 49 modem transmission processing unit (signal transmission unit) 50, 50A modem signal reception unit (reception unit, reception device) 51 modem reception processing unit (signal reception unit) 52) Coordinate decoding unit 53 Phase sum calculation unit 54, 54A Single tone determination unit (single tone determination unit on receiving side) 55 Gain control unit 56 Roll-off filter 57 Modulation unit 58 Carrier generation unit 59 D / A conversion unit 61a , 61b Multiplication unit 62a, 62b Square operation unit 63 Addition unit 64 Multiplication unit 65 Addition unit 66 Square operation unit 67 Addition unit 68 Reciprocal operation circuit 69a, 69b Delay unit 70a, 70b Multiplication unit 71a, 71b Addition unit 72a, 72b Multiplication unit 73a, 73b Rounding processing unit 75, 75a, 75b Delay unit 76 Phase error calculation detection unit 76-1 Level adjustment unit 77, 77A Feedback control unit 78 Phase error addition unit 79 Transmission unit 80 Receiving unit 81 Data switching unit 82 Coordinate decoding unit 83 Multiplication unit 84a, 84b Multiplication unit 85a, 85b Addition unit 86a, 86b Multiplication unit 87a, 87b Rounding unit 88a, 88b Multiplication Units 89a, 89b Addition unit 90a, 90b Multiplication unit 91a, 91b Rounding unit 101, 109 FAX terminal 102, 110 Telephone terminal 103, 108 Private branch exchange 104, 107 In-band ringer 105, 106 Modem 111 Private line 112 Transmission unit 113A / D conversion 114 Demodulation unit 115 Carrier generation unit 116 Roll-off filter 117 Judgment unit 118 Modem transmission processing unit 119 Receiving unit 120 Modem reception processing unit 121 Roll-off filter 122 Modulation unit 123 Carrier generation unit 124 D / A conversion unit 201 Communication device 202 Transmission unit (Transmitter) 202A Frequency shifter (first frequency shifter) 202B Coordinate determiner 203 Receiver (receiver) 203A Frequency shifter (second frequency shifter) 210, 210A Transmitter 211 A / D converter 212 Demodulation Unit 213 carrier generation unit 214 roll-off filter 215, 215A frequency shift unit (first frequency shift unit) 215-1 frequency shift operation unit 215-2 rounding processing unit 215-3 gain adjustment unit 215A-1 table 216 coordinate determination unit 217 Dem transmission processing unit (signal transmission unit) 220 reception unit 221 modem reception processing unit 221 (signal reception unit) 222 frequency reverse shift unit (frequency shift unit, second frequency shift unit) 223 roll-off filter 224 modulation unit 225 carrier generation unit 226 D / A conversion unit 2161 Coordinate judgment unit 2162 First normalization unit 2163 Decision point judgment unit 2164 Second normalization unit 2165 Phase error detection unit 2166 Phase error correction unit 21641 Reciprocal operation unit 21644 Multiplication unit 21644 Rounding unit

Continuation of front page (56) References JP-A-9-275453 (JP, A) JP-A-6-169360 (JP, A) JP-A-9-205500 (JP, A) JP-A 7-193659 (JP) JP-A-7-99512 (JP, A) JP-A-7-99513 (JP, A) JP-A-60-144037 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB Name) H04L 27/00-27/38 H04M 11/00 H04M 11/06

Claims (22)

(57) [Claims] An antenna including a tone signal having a single frequency.
The analog signal is input and the analog signal is
An analog / digital conversion unit for converting the signal into a signal, and a digital signal from the analog / digital conversion unit.
And a demodulation unit for demodulating with a carrier signal and decimation of the demodulated signal demodulated by the demodulation unit.
A decimation filter for performing the decimation process and a decimation process performed by the decimation filter.
The tone signal is a direct current
Determining a frequency shift unit for performing frequency shift so that the signal, the coordinates on the two-dimensional coordinate plane of the signal frequency shift has been performed by the frequency shifting unit, out of the coordinate determination result
And coordinates determination unit to force the signal to be transmitted on the signal output from the coordinate determination unit
A transmission device comprising a transmission unit. 2. A decision point judging unit which receives a coordinate judgment result from the coordinate judging unit and judges whether or not the same judgment result is continuous. And a phase difference detection unit that detects a phase difference between the phase of the signal subjected to the above and the phase of the output signal of the coordinate determination unit. The frequency shift is performed by using the phase difference detected by the phase difference detection unit. And a phase correction unit that corrects the phase of the frequency-shifted signal and outputs the signal to the coordinate determination unit.
The transmitting device according to the above. Wherein said frequency shift unit, an amount corresponding to the difference between the frequency of the carrier signal of the tone signal, to the demodulated signal subjected to the said decimation process
Characterized in that it is by Uni configured subjected to frequency shift Te, transmitting apparatus according to claim 1. 4. The apparatus according to claim 1, wherein a frequency shift amount in said frequency shift unit can be set according to a single frequency of said tone signal contained in said input analog signal. 2. The transmission device according to 1. 5. An antenna including a tone signal having a single frequency.
The analog signal is input and the analog signal is
An analog / digital conversion unit for converting the signal into a signal, and a digital signal from the analog / digital conversion unit.
About a carrier signal having a predetermined carrier frequency.
And a decimation unit for demodulating the demodulated signal demodulated by the demodulation unit.
A decimation filter for performing the decimation process and a decimation process performed by the decimation filter.
Processed demodulated signals are input continuously and input continuously.
A phase difference calculation unit for calculating a phase difference between two input signals , and a decimation process performed by the decimation filter.
The transmission-side single-tone determination unit that determines whether the processed demodulated signal is a single tone, and a demodulated signal from the decimation processing filter or a phase-difference calculation unit. a coordinate determination unit for performing a coordinate determination for any of the phase difference signal, and a signal transmission unit that transmits the determination result in the coordinate determination unit, the result of the judgment in the transmitting-side single tone determination section, the condensate
When the tone signal is not a single tone, the coordinate judging unit performs decimation by the decimation processing filter.
While the coordinate determination is performed on the demodulated signal subjected to the signal processing, if the demodulated signal is a single tone, the coordinate determination unit performs the coordinate determination on the phase difference signal from the phase difference calculation unit. A transmission device, characterized in that: 6. An antenna including a tone signal having a single frequency.
The analog signal is input and the analog signal is
An analog / digital conversion unit for converting the signal into a signal, and a digital signal from the analog / digital conversion unit.
About a carrier signal having a predetermined carrier frequency.
And a decimation unit for demodulating the demodulated signal demodulated by the demodulation unit.
A decimation filter for performing the decimation process and a decimation process performed by the decimation filter.
Processed demodulated signals are input continuously and input continuously.
A phase difference calculator for calculating a phase difference definitive between the two signals to be force, the output from the phase difference calculation unit, a coordinate determination unit for performing a coordinate determination, and the coordinate determination result from the coordinate determination unit, A phase error detection unit for detecting a phase error based on a phase difference calculation result from the phase difference calculation unit ; and a decimation process performed by the decimation process filter.
Management of decorated with demodulated signal includes a transmission-side single tone determination unit determines whether a single tone in the transmission side single tone determination section, determines that the demodulated signal is not a single tone If the demodulated signal is a single tone, the phase error information detected by the phase error detecting unit is fed back to the phase difference calculating unit. Characterized in that it is configured to stop feedback to the phase difference calculation unit of the phase error information detected by the error detection unit,
Transmission device. 7. The transmission-side single tone determination unit includes:
Decimation by the filter for
7. The apparatus according to claim 5, wherein the demodulated signal is determined to be a single tone when the demodulated signal is continuously input at a predetermined level for a predetermined number of times. The transmitting device according to the above. 8. A decompression-processed demultiplexed input signal that is continuously input a predetermined number of times before the phase difference calculation unit.
The decimation is performed based on the maximum level information of the modulation signal.
A gain control section for performing gain control on the demodulated signal subjected to the decimation processing, wherein the decimation in the single tone determination section on the transmission side is provided.
The processed demodulated signal continues at a certain level for a predetermined number of times
Whether or not it has been input, output from the gain control unit
The transmitting apparatus according to claim 7, wherein the transmitting apparatus is configured to make a determination based on the demodulated signal . 9. The transmission-side single-tone determination unit, wherein the decimation process is continuously performed a predetermined number of times .
7. The transmitting apparatus according to claim 5, wherein when the phase difference of the demodulated signal is constant, the demodulated signal is determined to be a single tone. 10. A transmission signal is received via a line.
A signal receiving unit that, with respect to received digital signals from the signal receiving unit, a tone signal having a specific frequency from a DC signal
A frequency shift unit that performs frequency shift for playing, versus the signal frequency shift has been performed in the frequency shifter
Interpolation that performs interpolation processing
Processing filter and data output from the interpolation processing filter.
Modulate digital signal with carrier signal with specific frequency
And a digital / analog converter for converting a digital signal modulated by the modulator into an analog signal. The frequency shifter controls the frequency and capacity of the tone signal.
The frequency corresponding to the difference from the rear signal frequency
Digital signals are frequency shifted.
A receiving device, characterized in that: 11. A signal receiving section for receiving a transmission signal from an opposite apparatus via a line and performing an inverse modem process, and for receiving digital signals from the signal receiving section,
A coordinate decoding unit for performing a decoding process; and a digital signal received from the coordinate decoding unit.
A phase sum calculation unit for calculating a phase sum of the input and continuously input digital signals, and a receiving side for determining whether or not the received digital signal is a single tone A single tone determining unit, and a digital signal or phase received from the signal receiving unit.
For any one of the phase sum signals from the sum operation unit,
Interpolation processing
And filter, Intapore at the interpolation processing filter
It includes a modulation section for performing modulation processing with the Deployment decorated with signals processing, based on the determination result in said receiving-side single tone determination unit,
If the received digital signal is not a single tone, the
The digital signal received from the signal receiver is interpolated.
If the received digital signal is determined to be a single tone while performing the
Processing for the phase sum signal from the section
A receiving device configured to perform the following . 12. The receiving-side single tone determining unit ,
Digital signal is input continuously at a certain level a predetermined number of times
If it is, the received digital signal is characterized in that it is configured to determine that a single tone, the receiving device according to claim 11. 13. The receiving-side single-tone determining unit receives the received digital signal at a constant level and continuously for a predetermined number of times.
Is determined by the gain control information from the opposite device.
Characterized in that it is configured to determine based on
The receiving device according to claim 12 . 14. The receiving-side single-tone determining unit determines that the received digital signal is a single tone when the phase difference between the received digital signals input continuously a predetermined number of times is constant. Characterized by being configured as follows,
The receiving device according to claim 11 . 15. A tone signal including a tone signal having a single frequency.
Input an analog signal, and digitize the analog signal.
An analog / digital converter for converting the signal into a digital signal;
Digital signals from the analog / digital converter
And a demodulator for demodulating with a carrier signal.
Performs demodulation on the demodulated signal
Filter for decimation processing and the decimation
Demodulation after decimation processing by processing filter
Signal so that the tone signal becomes a DC signal
For the demodulated signal subjected to the decimation processing,
A first frequency shift unit for performing a wave number shift, and the first frequency shift unit;
2D coordinate of frequency-shifted signal by shift unit
Coordinates for judging coordinates on the standard plane and outputting the coordinate judgment result
Transmitting a signal output from the determination unit and the coordinate determination unit;
A transmission unit including a signal transmission unit, a signal reception unit that receives a transmission signal via a line,
DC signal to digital signal received from the signal receiving unit
To reproduce a tone signal with a specific frequency from
A second frequency shift unit for performing a wave number shift, and the second frequency shift unit;
The signal shifted in frequency by the shift unit
Subjected to the Tapo configuration processing Intapore Deployment processing marks
Filter and the interpolation processing filter.
Carrier with specific frequency for digital signal to be input
A modulating section for modulating with a signal, and data modulated by the modulating section.
Digital / Analog to convert digital signals to analog signals
A second frequency shift unit including a analog conversion unit.
Between the frequency of the tone signal and the frequency of the carrier signal
Frequency corresponding to the above digital signal
Configuration with a receiver configured to apply shift
It characterized the Saretako, communication device. 16. The frequency shift according to claim 15 , wherein the frequency shift by the second frequency shift unit corresponds to an inverse frequency shift of the frequency shift by the first frequency shift unit.
The communication device as described. 17. A determination point determination unit to which a determination signal output from the coordinate determination unit is input, and which determines whether the input determination signals are continuously the same determination result, and a determination point determination unit. When it is determined that the same determination signal is continuously generated in step (a), the phase difference between the phase of the signal output from the first frequency shift unit and the phase of the signal output from the coordinate determination unit is determined. A phase difference detection unit, based on the phase difference obtained by the phase difference detection unit,
16. The communication device according to claim 15 , further comprising a phase correction unit configured to correct a phase of a signal output from the first frequency shift unit. 18. A system comprising a tone signal having a single frequency.
Input an analog signal, and digitize the analog signal.
An analog / digital converter for converting the signal into a digital signal;
Digital signals from the analog / digital converter
And a carrier signal having a predetermined carrier frequency.
Demodulator for demodulating the signal, and a demodulated signal demodulated by the demodulator
Decimation processing that performs decimation processing on
Filter and the decimation filter
Continuously input the demodulated signal after the
And the phase difference between two consecutively input signals
And a phase difference calculating section for calculating the
The demodulated signal subjected to decimation processing by the filter is
Transmitter single tone determination to determine if it is single tone
From the decimation filter described above.
Signal or the phase difference signal from the phase difference calculation unit
A coordinate determination unit for determining the coordinates of
And a signal transmitting unit for transmitting the determination result in
As a result of the determination in the transmission-side single tone determination unit,
If the signal is not a single tone,
Is decimation by the decimation processing filter.
Perform coordinate determination on the processed demodulated signal.
On the other hand, if the demodulated signal is a single tone, the coordinates
In the determination unit, the phase difference signal from the phase difference calculation unit
The transmitter configured to perform coordinate determination for
In addition to receiving the transmission signal from the opposite device via the line
A signal receiving unit for performing reverse modem processing, and
Performs coordinate decoding on the received digital signal
A coordinate decoding unit and a receiving digit from the coordinate decoding unit;
Data signals are input continuously and the data
Phase sum calculation for calculating phase sum in digital signal
And whether the received digital signal is a single tone
A receiving-side single-tone determining unit for determining
Digital signal from the unit or from the phase sum calculation unit
Interpolation for any of the phase sum signals
An interpolation processing filter for performing processing,
Interpolation with filters for interpolation processing
A modulation unit that performs modulation processing on a signal that has been subjected to
Includes a receiving portion formed by comprising a, the basis of the determination result in the reception side single tone determination unit
If the received digital signal is not a single tone,
For digital signals received from the
While the received digital signal is
If it is determined that the tone is a tone, the phase sum calculation unit
Interpolation processing for the phase sum signal from
A communication device , comprising: a receiving unit configured to perform the communication. 19. Including a tone signal having a single frequency.
Input an analog signal, and digitize the analog signal.
An analog / digital converter for converting the signal into a digital signal;
Digital signals from the analog / digital converter
And a carrier signal having a predetermined carrier frequency.
Demodulator for demodulating the signal, and a demodulated signal demodulated by the demodulator
Decimation processing that performs decimation processing on
Filter and the decimation filter
Decimation decorated with of demodulation signals continuously input of process
And the phase difference between two consecutively input signals
A phase difference calculating section for calculating, and an output from the phase difference calculating section.
A coordinate judging section for judging coordinates with respect to the force;
Determination result from the section and the phase difference from the phase difference calculation section
Phase error detection that detects the phase error based on the
And a decimation filter by the decimation processing filter.
Whether the demodulated signal that has been processed is a single tone
And a transmitting-side single tone determining unit for determining whether
In the receiving-side single tone determination section, the demodulated signal is converted to a single tone.
If it is determined that the phase error is not
The phase error information detected by
While the demodulated signal is a single tone
Is determined by the phase error detector,
The feedback of the phase error information to the phase difference calculation unit
With a transmitter configured to stop the
At the same time, receive the transmission signal from the
Digital modem performs inverse modem processing and receives judgment data
A signal receiving section for outputting as a signal, and receiving from the signal receiving section
Coordinate data to be subjected to coordinate decoding for digital signals
A code section and a digital signal received from the coordinate decoding section.
Number is input continuously and the digit is input continuously.
Phase sum calculation unit for calculating the phase sum of the total signal
And the phase sum signal from the phase sum calculation unit.
Interpolation processing file
Filter and interpolation filter.
Perform modulation processing on the signal that has been subjected to taporation processing.
And a modulation unit to be applied .
Communication device. 20. When the transmission data is subjected to coordinate determination and transmitted, it is determined whether or not the transmission data is a single tone, and if the transmission data is determined to be a single tone, , Between two consecutively input transmission data
Calculates the that phase difference, the calculation results of the phase difference and transmits by performing the coordinate determination, the case of the transmission data is determined to be a signal other than a single tone, the coordinates for the transmission data When the transmission data is received as reception data, it is determined whether or not the reception data is a single tone. When the reception data is determined to be a single tone, Is the space between two received data
That calculates the phase sum, as well as modulating the calculation result of the phase sum, the case where the received data is determined to be a signal other than a single tone, and characterized by modulating the said received data To send and receive modem signals. 21. When the transmission data is subjected to coordinate determination and transmitted, it is determined whether or not the transmission data is a single tone, and if the transmission data is determined to be a single tone, , Between two consecutively input transmission data
When the transmission data is determined to be a signal other than a single tone, when the transmission data is determined to be a signal other than a single tone, the transmission result of the continuous transmission data is calculated. A phase difference is calculated, the coordinate determination is performed on the calculation result of the phase difference, and transmission is performed. On the other hand, an error between the calculation result of the phase difference and the result of the coordinate determination is extracted, and a phase difference for the next transmission data is extracted. during operation, while performing correction of the error, when receiving the transmission data as received data, successively
A method of transmitting and receiving a modem signal, which calculates a sum of phases between two pieces of received data input by the modem and modulates the sum. 22. Regarding transmission data composed of a single tone, between two transmission data that are continuously input
Definitive calculates the phase difference, and transmits by performing the coordinate determination on the operation result of the phase difference, when receiving the transmission data as received data, successively
A phase sum between two pieces of received data that are input to the modem and modulating the calculation result of the phase sum.