JP3702532B2 - Telephone equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wireless telephone device such as a mobile phone and a car phone.
[0002]
[Prior art]
For example, wireless telephone devices such as car phones, cellular phones, cordless phones, etc. that adopt a digital signal processing method are widely used, but as functions as a telephone device, for example, dial tone sound, hold sound, busy In order to generate a tone such as a sound and output it to a speaker or transmit it, a tone generating circuit unit such as DTMF (Dual Tone Multi Frequency) is provided.
[0003]
A configuration example of a conventional wireless telephone device is shown in FIG.
The telephone device is provided with a microphone 31 that collects the voice generated by the user, and an audio signal (transmission audio signal) obtained by the microphone 31 is connected to the A / D converter 33 via the microphone amplifier 32 and the T1 terminal of the switch 36. To be supplied.
The A / D converter 33 is a so-called 1-bit A / D converter composed of, for example, a ΔΣ modulator 34 and a decimation filter 35.
[0004]
After transmission voice by the A / D converter 33 is a digital data S _D is band-limited by the band-pass filter 37, a predetermined modulation process is performed in the transmission processing unit 38. For example, encoding processing, TDMA (time division multiplexing) processing, differential encoding processing, and the like are performed at the digital data stage, and after being converted into an analog signal, orthogonal modulation is performed to form a transmission signal.
The transmission signal output as the analog signal S _A from the transmission processing unit 38 is subjected to RF amplification processing in the transmission amplification unit 39, supplied to the antenna 41 via the To terminal of the antenna switch 40, and transmitted for output. .
[0005]
The signal received by the antenna 41 is supplied to the reception amplification unit 42 via the Ti terminal of the antenna switch 40, and RF amplification processing is performed. In the reception processing unit 43, predetermined reception demodulation processing, for example, synchronous detection, A / D conversion, differential decoding, TDMA processing, decoding, and the like are performed, and reception voice data is output as digital data _SD . The received audio data is band-limited by the bandpass filter 44 and then input to the D / A converter 46.
The D / A converter 46 includes a noise shaper 47 and an analog integration circuit 48, that is, a 1-bit D / A converter.
The received voice signal converted to an analog signal by the D / A converter 46 is supplied to the power amplifier 49 via the T1 terminal of the switch 45 and amplified, and is output from the speaker 50 as a call voice from the other party.
[0006]
The control unit 52 is formed by a microcomputer and controls the operation of each circuit unit of the transmission system / reception system described above.
Further, the operation unit 53 is provided with various keys for the user to start / end a call and input operations such as a telephone number, and the control unit 52 transmits / receives according to operation information from the operation unit 53. Control each part for.
The display unit 54 is configured by a small display device such as a liquid crystal panel, for example, and displays a dial number input by the user, a message, a call status, and the like based on a display control signal from the control unit 52.
[0007]
The sound source 51 is provided to generate a tone sound having an arbitrary frequency.
The sound source 51 may be a memory table having data of a certain sampling point (for example, D1 to D4) of one sine wave as shown in FIG. 4A, for example, as a simple arbitrary frequency generation circuit. .
Then, each data D1~D4 from the memory table successively to read out at a timing based on the clock CK _T.
[0008]
Thus, for example, the control unit 52 be supplied to the tone generator 51 to set the clock CK _T to a certain frequency, a sinusoidal signal of a certain frequency as shown in Figure 4 (b) is output as tone signal S _AT, in the case where the control unit 52 to lower the frequency of the clock CK _T, lower frequency of the sinusoidal signal as shown in FIG. 4 (c) is output as tone signal S _aT. That is, a tone sound signal with an arbitrary frequency can be output. For example, the control unit 52 outputs a tone sound signal with a predetermined frequency from the sound source 51 in accordance with a number in the dial operation of the user at the operation unit 53. Audio can be output according to the operation.
[0009]
The tone sound signal S _AT output from the sound source 51, that is, the data D1 to D4 at this time, is converted into an analog tone sound signal by the D / A converter 55. The D / A converter 55 may be any type such as a resistance ladder type.
When the tone sound is generated, the control unit 52 connects the switches 36 and 45 to the T2 terminal. Therefore, the tone sound signal is output from the speaker 50 through the power amplifier 49 and further digitally output by the A / D converter 33. When the data is converted and sent to the transmission processing unit 38, dial transmission is performed.
[0010]
[Problems to be solved by the invention]
However, such a telephone device has the following problems.
First, the D / A converter 55 must be provided corresponding to the sound source 51, which causes a problem that the circuit scale increases. In addition, there also arises a situation that the D / A converter 55 itself must be recreated in accordance with a change in the semiconductor design rule or resistance value when changing the specification of the device.
[0011]
Further, the D / A converter 55 and the ΔΣ modulator 34 have a large current during operation. Therefore, when transmitting a tone sound from the sound source 51 that needs to operate these two circuit units, the power consumption is large. There is a problem of becoming. In particular, in a telephone device using a battery (dry battery / rechargeable battery) as a power source such as a mobile phone, it is very unpreferable that power consumption is large.
[0012]
[Means for Solving the Problems]
In view of such problems, it is an object of the present invention to realize simplification of a circuit configuration relating to tone generation and reduction of operating power in a telephone device.
[0013]
For this reason, the digital tone data output from the sound source means can be output as tone sound from the speaker means via the D / A conversion means in which the digital data output from the reception demodulation means is analog audio data. In addition, the D / A conversion means and the A / D conversion means for converting the input audio signal from the microphone means into digital data are supplied to the transmission modulation means so as to be transmitted and output.
[0014]
In particular, the A / D conversion means is formed by a ΔΣ modulator and a decimation filter, and the D / A conversion means is constituted by a noise shaper and an integration circuit. The digital tone data output from the sound source means is converted into 1-bit stream data by the noise shaper in the D / A conversion means, and the 1-bit stream data is converted into an analog audio signal by the integration circuit and supplied to the speaker means. The 1-bit stream data from the noise shaper is supplied to the decimation filter to become digital data, which is supplied to the transmission modulation means.
[0015]
That is, according to the present invention, the circuit scale is reduced by not providing a tone output dedicated D / A converter or the like of the tone generator means, and no dedicated D / A converter is provided. By eliminating the operation of the ΔΣ modulator in the A / D converter, power consumption can be saved.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a telephone device of the present invention will be described with reference to FIGS.
A block diagram of the wireless telephone device of this example is shown in FIG.
The telephone device is provided with a microphone 1 that collects the voice generated by the user, and an audio signal (transmission audio signal) obtained by the microphone 1 is subjected to ΔΣ modulation constituting an A / D converter 3 via a microphone amplifier 2. Is input to the device 4.
The output of the ΔΣ modulator 4 is supplied to the decimation filter 5 that also constitutes the A / D converter 3 via the T1 terminal of the switch 6.
[0017]
The A / D converter 3 is a so-called 1-bit A / D converter composed of a ΔΣ modulator 4 and a decimation filter 5.
ΔΣ modulation is an A / D conversion method in which the difference (delta) between an analog input and digitized data one clock before is converted back to an analog signal is integrated (sigma). Therefore, the delta-sigma modulator 4 has a differential amplifier for taking the difference between the analog input signal from the microphone 1 and the digitized data one clock before converted back to the analog signal, and the output of the differential amplifier. It has an integrator for integration processing, a 1-bit D / A converter (comparator) for the output of the integrator, and a 1-bit A / D converter for analogizing the output of this 1-bit D / A converter and feeding it back to the differential amplifier. Configured. An extremely high frequency is used as the sampling frequency. For example, a sampling clock that is several tens to several hundred times as many as a sampling clock used for A / D conversion of a normal audio signal is used.
[0018]
As already known, in such a ΔΣ modulator 4, so-called noise shaping operation and oversampling operation are executed, and the output (noise shaping output) of the ΔΣ modulator 4 is a 1-bit signal subjected to PDM (pulse density modulation). Signal. Such 1-bit PDM bit stream output is converted into parallel digital data having a predetermined number of bits by a decimation filter.
[0019]
After transmission voice by the A / D converter 3 is the digital data S _D is band-limited by the band-pass filter 37, a predetermined modulation process is performed in the transmission processing unit 38.
The transmission processing unit 8 is configured as shown in FIG.
Transmission audio data as parallel digital data input to the transmission processing unit 8 is first subjected to encoding processing (audio codec processing) by the encoding processing unit 61. Subsequently, the TDMA processing unit 62 performs TDMA (time division multiplexing) processing as frame processing, and the signal subjected to the TDMA processing is supplied to a differential encoding unit 63 which is a digital modulation / demodulation unit, so that a differential code is obtained. Is applied. The D / A converter 64 converts the signal into an analog signal, and the quadrature modulator 65 performs π / 4 shift QPSK modulation.
[0020]
In this way, the transmission processing unit 8 performs modulation in the digital stage and the analog stage, and the transmission signal output as the analog signal S _A is supplied to the transmission amplification unit 9 including a linear power amplifier and the like as a transmission signal. It is processed. Then, the signal is supplied to the antenna 11 via the To terminal of the antenna switch 10 and transmitted.
The antenna switch 10 is capable of switching the terminal To and the terminal Ti at high speed during a call during a transmission frame period and a reception frame period, and the control is performed by the control unit 22.
[0021]
A signal received by the antenna 11 is supplied to the reception amplifying unit 12 via the Ti terminal of the antenna switch 10 and subjected to RF amplification processing. Then, reception demodulation processing is performed in the reception processing unit 13.
The reception processing unit 13 is configured as shown in FIG. 2B, for example, and the output of the reception amplification unit 12 is first synchronously detected by the synchronous detector 66, and then is converted into digital data by the A / D converter 67. Is done. The differential decoding processing unit 68 performs differential decoding processing and supplies the differential decoding processing unit 68 to the TDMA processing unit 69.
The reception data extracted by the TDMA processing unit 69 is subjected to decoding and error correction processing by the decoding processing unit 70, and is output from the reception processing unit 13 as reception voice data that has been received and demodulated.
[0022]
The received audio data is filtered by a band pass filter 14 including an interpolation filter, and then input to the D / A converter 16 via the T1 terminal of the switch 15.
The D / A converter 16 is composed of a noise shaper 17 and an analog integration circuit 18. That is, the noise shaper 17 performs an oversampling / noise shaping process on parallel digital data to generate a 1-bit data stream (a coarse / fine wave by PDM). ) And is further integrated by an integrator 18 to be converted into an analog signal to be a 1-bit D / A converter.
[0023]
The reception voice signal converted into an analog signal by the D / A converter 16 is supplied to the power amplifier 19 and amplified, and is output from the speaker 20 as a call voice from the other party.
[0024]
The control unit 22 is formed of a microcomputer and controls the operation of each circuit unit of the transmission system / reception system described above.
The operation unit 23 is provided with various keys for the user to start / end a call and input operations such as a telephone number, and the control unit 52 transmits / receives according to operation information from the operation unit 53. Control each part for.
For example, the operation unit 23 includes a dial key, a call start (off hook) key, a call end (on hook) key, a speed dial key, a redial key, a one-touch dial key, and the like. Control of each required part is performed in accordance with operations such as transmission operation, transmission / reception operation, and redial transmission, and the operation requested by the telephone device is executed.
[0025]
The display unit 24 is configured by a small display device such as a liquid crystal panel, for example, and displays a dial number input by the user, a message, a call status, and the like based on a display control signal from the control unit 52.
[0026]
The sound source 21 is provided to generate a tone sound having an arbitrary frequency.
As with the sound source 51 in FIG. 3 described above, the sound source 21 is, for example, as a simple arbitrary frequency generation circuit, for example, data at a certain sampling point (for example, D1 to D1) as shown in FIG. A memory table having D4) may be used.
[0027]
Then, the data D1 to D4 are sequentially read from the memory table at a timing based on the clock CK _T. Therefore, the control unit 22 variably outputs the frequency of the clock CK _T , which has been described with reference to FIG. Thus, a sine wave having an arbitrary frequency can be output as a tone sound signal. For example, the control unit 22 outputs a tone sound signal of a predetermined frequency from the sound source 21 in accordance with the number in the dial operation of the user at the operation unit 23 or according to on-hook / off-hook operation, incoming call, transmission state, etc. By doing so, it is possible to output various necessary tone sounds such as dial tone, hold tone, etc. [0028]
In this example, the tone sound signal output from the sound source 21, that is, digital data that becomes data D <b> 1 to D <b> 4 in the example of FIG. 4 is supplied to the T <b> 2 terminal of the switch 15.
When the tone sound is generated, the control unit 22 connects the switches 6 and 15 to the T2 terminal. Therefore, the tone sound data is subjected to oversampling / noise shaping processing by the noise shaper 17, and the PDM1 bit stream data Is done. The data is supplied to the integrator 18 and the T2 terminal of the switch 6.
[0029]
The 1-bit tone audio data supplied to the integrator 18 is converted into an analog signal by integration processing and output from the speaker 20 via the power amplifier 19. This allows the user to hear the tone.
[0030]
Further, 1-bit tone audio data at the output stage of the noise shaper 17 is input to the decimation filter 5 via the T 2 terminal of the switch 6. That is, it is converted into parallel digital data and is sent to the transmission processing unit 8 via the bandpass filter 7 and tone sound transmission such as dial transmission is executed.
[0031]
In other words, in this example, for the digital data as the tone sound from the sound source 21, a dedicated D / A converter is not provided, and the tone sound speaker output is realized by using the receiving D / A converter 16. ing.
Further, the output data (1 bit) of the noise shaper 17 in the D / A converter 16 is supplied to the decimation filter 5 of the A / D converter 3 to obtain parallel digital data having a predetermined number of bits, thereby transmitting a tone sound. Output is realized.
In this way, the necessary operation can be performed without providing a dedicated D / A converter for the sound source 21, thereby simplifying the circuit configuration and superiority when changing specifications (D / A conversion). No need to remake the vessel).
[0032]
Further, in this example, the operation of the ΔΣ modulator 4 in the A / D converter 3 is not required at the time of tone sound transmission, so that a large current does not flow through the ΔΣ modulator 4 at the time of tone sound transmission, and power consumption is reduced. Can save. In addition, since there is no dedicated D / A converter for the sound source 21, the power consumption of this D / A converter can be saved as compared with the conventional telephone device. As a result, it is possible to save power consumption during use, thereby extending the battery life.
[0033]
【The invention's effect】
As described above, in the telephone device of the present invention, the digital tone data output from the sound source means is generated from the speaker means via the D / A conversion means in which the digital data output from the reception demodulation means is analog audio data. In addition to being able to output as audio, the D / A conversion means and the A / D conversion means for converting the input audio signal from the microphone means into digital data are supplied to the transmission modulation means for transmission and output. Therefore, there is no need to provide a dedicated D / A conversion means for the sound source means, and there is an effect that the circuit configuration can be simplified and superiority at the time of specification change can be realized.
[0034]
Further, the A / D conversion means is constituted by a ΔΣ modulator and a decimation filter, the D / A conversion means is constituted by a noise shaper and an integration circuit, and the digital tone data output from the sound source means is D / A conversion means. 1 bit stream data is converted into an analog audio signal by an integration circuit and supplied to speaker means, and 1 bit stream data from the noise shaper is supplied to a decimation filter and converted to digital. The data is supplied to the transmission modulation means. As a result, the operation of the ΔΣ modulator in the A / D converter of the transmission system becomes unnecessary during tone transmission, so that a large current is not consumed, and the D / A conversion means dedicated to the sound source means is not provided as described above. Since the power consumption is unnecessary, there is an effect that significant power reduction can be realized.
[Brief description of the drawings]
FIG. 1 is a block diagram of a telephone device according to an embodiment of the present invention.
FIG. 2 is a block diagram of a transmission processing unit and a reception processing unit of the telephone device according to the embodiment.
FIG. 3 is a block diagram of a conventional telephone device.
FIG. 4 is an explanatory diagram of a simplified sound source.
[Explanation of symbols]
1 microphone, 3 A / D converter, 4 ΔΣ modulator, 5 decimation filter, 6, 15 switch, 7, 14 band pass filter, 8 transmission processing unit, 10 antenna switch, 11 antenna, 13 reception processing unit, 16 D / A converter, 17 noise shaper, 18 integrator, 20 speaker, 21 sound source, 22 control unit, 23 operation unit

Claims (2)

A microphone means for inputting a transmitted voice;
A / D conversion means for converting the input audio signal from the microphone means into digital data;
Transmission modulation means for performing predetermined transmission modulation processing on the digital data output from the A / D conversion means;
A transmission / reception means capable of transmitting a signal output from the transmission modulation means and receiving a signal;
A reception demodulation means for converting the signal received by the transmission / reception means into digital data and performing a predetermined reception demodulation process;
D / A conversion means for converting the digital data output from the reception demodulation means into analog audio data;
Speaker means for outputting analog voice data output from the D / A conversion means as received voice;
Sound source means capable of outputting digital tone data having a predetermined tone waveform;
With
The digital tone data output from the sound source means can be output as tone sound from the speaker means via the D / A conversion means, and via the D / A conversion means and the A / D conversion means. The telephone apparatus is configured to be supplied to the transmission modulation means and transmit and output. The A / D conversion means is formed by a ΔΣ modulator and a decimation filter,
The D / A conversion means includes a noise shaper and an integration circuit,
The digital tone data output from the sound source means is converted into 1-bit stream data by the noise shaper in the D / A conversion means, and the 1-bit stream data is converted into an analog audio signal by the integration circuit to the speaker means. 2. The telephone according to claim 1, wherein 1-bit stream data from the noise shaper is supplied to the decimation filter as digital data and supplied to the transmission modulation unit. apparatus.

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