JP4353326B2 - Audio compression multiplexer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a voice compression multiplexing apparatus, and more particularly to a plurality of voice lines using a digital line by installing a means for compressing and coding a voice signal by installing it between a subscriber line switch and a telephone. The present invention relates to a voice compression multiplexing apparatus that can suppress a transmission band when multiplexing and transmitting.
[0002]
[Prior art]
Conventionally, a voice signal is often compressed and encoded as much as possible to multiplex and take measures to improve line efficiency, which is important for communication. Also in the subscriber line, a voice compression and multiplexing apparatus has been introduced that compresses and encodes a voice signal in order to multiplex a speech path between the subscriber line switch and the telephone.
[0003]
FIG. 3 is a diagram illustrating a configuration example of a conventional audio compression multiplexing apparatus.
The figure shows an example in which a subscriber line switch side voice compression multiplexing apparatus 3 and a telephone side voice compression multiplexing apparatus 4 are installed between the subscriber line switch 1 and the telephones 2a and 2b. . That is, in this example, seven subscriber lines between the subscriber line switch 1 and the telephone set 2 are connected to the subscriber line switch side voice compression multiplexing apparatus 3 and the telephone side voice compression multiplexing apparatus 4. In the meantime, it is multiplexed and transmitted / received on a pair of transmission lines.
[0004]
The subscriber line switch side voice compression multiplexing apparatus 3 compresses and encodes a voice signal, decompresses the voice signal, and decodes the first voice path part 5a to a seventh speech path part 5b. The multiplexed converter 6 that multiplexes the seven speech paths from the first speech path section 5a to the seventh speech path section 5b, and the multiplexed signal from the telephone-side voice compression multiplexer 4 And a demultiplexing unit 7 for separation.
On the other hand, the telephone-side voice compression multiplexing apparatus 4 is similar to the above-mentioned subscriber line switch-side voice compression multiplexing apparatus 3 in that the demultiplexing unit 8, the multiplexing conversion unit 9, and the first speech path units 10a to 10a. And a seventh call path unit 10b.
[0005]
The first communication path unit 5 a includes a REP (repeater) 11 that relays a control signal input / output to / from the subscriber line switch 1 and a two-wire line (subscriber line) connected to the subscriber line switch 1. A hybrid transformer (H) 12 for converting into a four-wire circuit, a voice encoding unit 13 for compressing a voice signal and coding it together with a control signal, and voice decoding for decoding the coded voice signal and the control signal Part 14. This configuration is the same up to the seventh speech path unit 5b.
Similarly to the first speech path unit 5a, the first speech path unit 10a includes a speech decoding unit 15 that decodes the encoded speech signal and the control signal, and compresses the speech signal. A voice encoding unit 16 that encodes with a control signal, a hybrid transformer (H) 17 that converts a four-wire circuit to a two-wire circuit, and a REP 18 that relays a control signal input to and output from the telephone 2a are provided.
[0006]
The operation of FIG. 3 will be described. In the figure, seven communication lines (subscriber lines) connected to the subscriber line switch 1 are connected to the subscriber line switch side voice compression multiplexing apparatus 3 and seven telephones 2 are connected to the telephone line side voice compression multiplexing. The voice compression and multiplexing apparatus 3 for the subscriber line switch side is connected to the apparatus 4, and the voice signal from the subscriber line switch 1 is connected to the telephone line side voice compression and multiplexing apparatus 4. For example, the signal is voice-compressed to 8 kb / s using the CS-ACELP voice coding method, multiplexed, and transmitted. Here, an example is shown in which the subscriber line switch side voice compression multiplexing apparatus 3 and the telephone side voice compression multiplexing apparatus 4 are connected via a 64 kb / s digital line.
[0007]
First, the case where a call is made from the subscriber line switch 1 to the telephone 2a will be described. The 16 Hz calling signal output from the subscriber line switch 1, the polarity information of the DC signal, and the like are shown in the REP 11 provided in the first communication path unit 5a. And input to the voice encoding unit 13. The voice signal is converted from a two-wire circuit to a four-wire circuit by the hybrid transformer 12, and the voice signal from the subscriber line switch 1 is input to the voice encoding unit 13.
[0008]
The voice encoding unit 13 compresses and encodes the voice signal to 8 kb / s and outputs it to the multiplex conversion unit 6, and the 16 Hz calling signal, the polarity information of the DC signal, etc. are sent to the multiplex conversion unit 6 as control bits. input.
Next, the multiplex conversion unit 6 multiplexes the compressed digital voice signals of the seven speech paths, and sends this multiplexed signal to the telephone-side voice compression multiplex device 4 via a 64 kb / s digital line. To do.
[0009]
In the voice compression multiplexing apparatus 4 on the telephone side, the received multiplexed signal is separated for each speech path by the demultiplexing unit 8, and the separated compressed digital voice signal is associated with each speech path, and the first speech path unit 10a to the seventh speech path unit 10b.
In the first speech path unit 10a, the voice decoding unit 15 decodes the voice signal and the control signal for the telephone 2 into an analog signal, and the voice signal is output to the hybrid transformer 17 and the control signal is output to the telephone 2a via the REP 18. To do.
[0010]
On the other hand, in the case of making a call from the telephone 2a, information on the intermittent signal such as a loop signal and dial pulse of the DC circuit from the telephone 2a is sent to the first speech path unit 10a of the voice compression multiplexing apparatus 4 for the telephone. Detected by the provided REP 18 and input to the voice encoding unit 16.
The voice signal from the telephone 2 a is converted from a two-wire line to a four-wire line by the hybrid transformer 17 and output to the voice coding unit 17.
In the voice encoding unit 17, an analog voice signal is voice-compressed into an 8 kb / s digital signal and encoded and input to the multiplex conversion unit 9, and intermittent signals such as loop signals and dial pulses of the DC circuit are controlled. It is input to the multiple conversion unit 9 as bits.
[0011]
Next, the multiplex conversion unit 9 sends the multiplexed signal obtained by multiplexing the compressed digital voice signals of the seven speech paths to the subscriber line switch side voice compression multiplexing apparatus 3 via the 64 kb / s digital line. To do.
The subscriber line switch side voice compression multiplexing apparatus 3 separates the received multiplexed signal for each speech path by the demultiplexing unit 7, and the separated compressed digital voice signal is transmitted from the first speech path unit 5 a to the seventh channel. Input to the communication path section 5b.
In the first communication path unit 5a, the voice decoding unit 14 decodes the voice signal and the control signal for the subscriber line switch 1 into an analog signal. The voice signal is sent to the hybrid transformer 12 and the control signal is sent to the subscriber via the REP 11. Output to switch 1.
[0012]
Also, in recent telephone exchange networks, a caller number notification service (number display) is provided, and the above-described conventional voice compression multiplexing apparatus has a request corresponding to this caller number notification function.
The above-mentioned caller ID notification service is a service for notifying the caller ID of the caller at the telephone 2 before responding to the incoming call when receiving an incoming call from the subscriber line switch 1. The calling party number is notified to the telephone set 2 by a modem signal of 1200 B (baud rate) according to a predetermined procedure from the subscriber exchange 1 before calling the telephone set 2.
[0013]
However, if the modem signal is compressed and transmitted to 8 kb / s in the above-described voice compression and multiplexing apparatus, the necessary band component cannot be sufficiently received when the modem signal is received on the telephone side, and the modem is demodulated. Bit error.
Therefore, the modem signal used for the caller ID notification function needs to be demodulated into 1200B data, converted into a signal with a transmission rate of 8 kb / s without being compressed, and output.
Therefore, in the voice encoding unit that performs the voice compression processing, it is identified whether the input voice signal is a voice signal for a call or a modem signal for notifying the caller number. The circuit is switched so as to perform dedicated digitization processing, and identification for this switching is performed by identifying the operation sequence determined for the caller ID notification function and specifying the modem signal. .
[0014]
FIG. 4 shows a frame configuration of the audio compression multiplexing apparatus.
(C) of the figure shows a frame configuration of a signal output to the transmission path by the voice compression multiplexing apparatus that multiplexes the seven speech paths. This frame is composed of a control slot (TS1) composed of control signals and synchronization bits for seven speech paths, and main signal slots (TS2 to TS8) of seven speech paths consisting of voice compression signals or modem signals. Thus, a transmission rate of 64 kb / s is obtained by transmitting one 64-bit frame in 1 msec.
The bit string (d) constituting the main signal is not provided with a synchronization establishment bit, and is synchronized with the synchronization bit included in the control slot (TS1) shown in (c) at a timing of 10 msec intervals. A signal is created, and the bit string (d) constituting the main signal is synchronized with the timing signal.
The main signal shown in the above bit string (d) has a transmission rate of 8 kb / s by transmitting 80 bits at 10 msec.
Therefore, as a method of synchronizing the main signal with a timing signal having an interval of 10 msec based on the synchronization bit included in the control slot, first, a multi-frame composed of 5 frames is generated as shown in FIG. As shown in FIG. 6, a multi-frame is generated by 6 multi-frames to obtain a multi-frame of 30 msec, and the 10 msec timing signal is synchronized with the head of the multi-frame.
[0015]
[Problems to be solved by the invention]
However, the conventional audio compression and multiplexing apparatus has the following problems. That is, in the voice encoding unit 13, each of the voice compression process and the modem signal digitization process is performed in the operation of identifying the modem signal and switching the voice compression process to the modem signal digitization process and the restoration operation. The switching operation and the recovery operation are performed asynchronously regardless of the frame synchronization functioning for recognizing the bit position in the frame generated by the multiple conversion unit 6. Specifically, in the voice encoding unit and the voice decoding unit, the modem signal is identified and the voice compression processing is switched to the digitization processing of the modem signal, and the restoration operation is performed asynchronously with the timing signal of 10 msec. The frame synchronization is lost.
As a result, until the multiplex conversion unit 6 establishes frame synchronization again, an operation error occurs in the voice decoding unit 15, and abnormal sound is transmitted to the telephone set 2 side to deteriorate the call quality.
[0016]
The present invention has been made to solve such a problem, and it is possible to provide a caller ID notification service without degrading call quality related to switching for multiplexing transmission of modem signals at the time of caller ID notification. An object of the present invention is to provide an audio compression multiplexing apparatus that can cope with this.
[0017]
[Means for Solving the Problems]
In order to achieve the above object, a voice compression and multiplexing apparatus according to the present invention is a voice compression and multiplexing apparatus that is installed opposite to a subscriber line between a switch and a telephone and compresses and multiplexes a voice signal. The audio compression multiplexing apparatus on the side determines whether or not the audio signal is a modem signal for notifying the caller number to the audio encoding unit that converts the audio signal from the exchange into a digital signal by encoding the audio signal. A switching information detection unit for detecting the output, a voice / data transmission unit for selecting an output from the voice encoding unit or the caller ID data transmission unit based on the switching signal from the switching information detection unit, a control signal, and the A control signal sending unit that encodes the switching signal, and the voice compression multiplexing device on the telephone side includes the control unit in the voice decoding unit that outputs the decoded voice signal to the telephone A control signal receiving unit for decoding the signal and the switching signal, a voice / data receiving unit for distributing the received signal to the voice decoding unit or the caller ID data receiving unit based on the decoded control signal, and the decoding By the voice / data switching unit for selecting the output from the voice decoding unit or caller ID data receiving unit based on the converted control signal, and by the voice / data switching unit based on the decoded control signal An abnormal noise removing unit that suppresses abnormal noise generated at the time of switching and a D / A conversion unit that converts a digital signal from the abnormal noise removing unit into an analog signal are provided. For this reason, at the time of switching and recovery when a modem signal notifying the caller number is received, the noise removing unit forcibly sets the level of the audio signal to zero for a predetermined time. It is possible to prevent deterioration in the quality of calls to the telephone.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on illustrated embodiments.
FIG. 1 shows an embodiment of a configuration of a speech path unit of a voice compression multiplexing apparatus according to the present invention. Although not shown, the subscriber line switch side voice compression multiplexing apparatus 3 and the telephone side voice compression multiplexing apparatus 4 face each other between the subscriber switch 1 and the plurality of telephones 2 as in the conventional case. It is assumed that the transmission side communication path unit 19 shown in (a) is in the voice exchange multiplexing apparatus 3 on the subscriber line switch side, and the reception side communication path unit 20 shown in (b) is on the voice on the telephone side. It is provided in the compression multiplexer 4. Further, here, in order to explain the operation related to the caller number notification function from the subscriber exchange 1, description of the functional blocks relating to the call direction from the telephone set 2 to the subscriber exchange 1 is omitted.
[0019]
In the configuration of FIG. 1, a transmission side communication path 19 includes a REP (repeater) 11 that relays a control signal input / output to / from the subscriber line switch 1 and a two-wire line connected to the subscriber line switch 1. A hybrid transformer (H) 12 that converts (subscriber line) into a four-wire line for each direction of uplink / downlink, and a voice code that compresses a voice signal from the subscriber switch 1 and encodes it together with a control signal Part 21.
Based on the control signal detected by the REP 11, the voice encoding unit 21 determines whether the input signal from the subscriber exchange 1 is a voice signal for a call or a modem signal for notifying a caller number. Switching information detection unit 22 that outputs a switching signal for switching the voice code processing method by detecting the signal, and after the analog voice signal from the hybrid transformer 12 is digitized to 64 kb / s, the voice is further compressed to 8 kb / s. A voice encoding unit 23 that encodes the data, and a caller number data transmission unit 24 that demodulates the modem signal for notifying the caller number from the hybrid transformer 12 into 1200 B data and then outputs the data at a transmission rate of 8 kb / s. Based on the control of the switching signal output by the switching information detection unit 22, the output from the voice encoding unit 23 and the caller ID data transmission unit 24 A voice / data transmission unit 25 that switches to select one of the outputs and transmits it to the multiplex conversion unit, and a control signal that encodes and transmits the switching signal detected by the switching information detection unit 22 and the control signal for the telephone A sending unit 26 is provided.
[0020]
On the other hand, the reception speech path unit 20 includes a voice decoding unit 27 that decodes the encoded compressed voice signal or caller ID data and the control signal, and a hybrid transformer that converts a four-wire line into a two-wire line. (H) 17 and a REP 18 that relays a control signal input / output to / from the telephone 2.
The voice decoding unit 27 receives the switching signal separated by the demultiplexing unit and the control signal for the telephone 2, outputs the switching signal to the switching information output unit 29 and outputs the control signal to the REP 18. A switching information output unit 29 for distributing the switching signal from the control unit 28, the switching signal from the control signal receiving unit to the voice / data receiving unit 30, the voice / data switching unit 33, and the abnormal noise removing unit 34; A voice signal separated for each speech path or a modem signal notifying the caller number is received, and based on the switching signal from the switching information output unit 29, the voice signal is sent to the voice decoding unit 31, and the modem signal is the caller number. The audio / data receiving unit 30 to be output to the data receiving unit 32 and the audio signal compressed to 8 kb / s input from the audio / data receiving unit 30 are decompressed. The voice decoding unit 31 for decoding the original 64 kb / s digital signal, and the 1200B caller ID data converted to the transmission rate of 8 kb / s input from the voice / data receiving unit 30 are converted into 64 kb / s. On the basis of the control of the switching signal from the switching information output unit 29 and the output from the voice decoding unit 31 and the calling number data receiving unit 32 based on the control of the switching signal from the switching information output unit 29. The voice / data switching unit 33 that switches and outputs one of the outputs from the output, and the decompressed 64 kb / s digital voice signal and the 64 kb / s digital modem signal that notifies the sender number are switched and output. An abnormal noise removing unit 34 that eliminates noise generated at the time of generation and a D / A conversion unit 35 that converts a digital signal into an original analog signal are provided.
[0021]
Next, an operation sequence of the caller ID notification function necessary for modem signal identification in the switching information detection unit 22 of the speech encoding unit 21 will be described.
FIG. 2 is a diagram showing an operation sequence when the caller number is notified from the subscriber line exchange 1 to the telephone set 2 through the voice compression and multiplexing apparatuses 3 and 4.
The operation sequence shown in this figure starts when a call is received from the subscriber line switch 1 to the telephone set 2. That is, the subscriber line switch 1 first reverses the polarity of the DC power supplied to the subscriber line to the subscriber line switch side voice compression multiplexer 3 (hereinafter referred to as multiplexer A). At the same time, as a receiving terminal activation signal for activating the telephone 2, a 16 Hz signal is intermittently output at 0.5 sec ON and 0.5 sec OFF.
[0022]
The polarity inversion signal and the receiving terminal activation signal are input to the telephone set 2 through the multiplexing apparatus A and the voice compression multiplexing apparatus 4 on the telephone side (hereinafter referred to as multiplexing apparatus B). The DC loop is closed as a primary response to the signal and the receiving terminal activation signal.
When the primary response signal from the telephone set 2 is input to the subscriber line switch 1 via the multiplexer B and the multiplexer A, the subscriber line switch 1 uses the 1200B signal to notify the caller number. The modem is activated, and a modem signal (sender number information) according to a predetermined data format is output by an asynchronous method.
[0023]
Next, the modem signal from the subscriber exchange 1 is input to the telephone 2 via the multiplexer A and the multiplexer B, and the telephone 2 demodulates the 1200B modem and displays the caller ID. The DC loop is opened as a reception completion signal.
Then, when the reception completion signal from the telephone set 2 is input to the subscriber line switch 1 via the multiplexer B and the multiplexer A, the subscriber line switch 1 serves as a calling signal for calling the telephone set 2. Outputs 16 Hz intermittently for 1 sec ON and 2 sec OFF.
[0024]
Next, the calling signal from the subscriber exchange 1 is input to the telephone set 2 through the multiplexing apparatus A and the multiplexing apparatus B, and the telephone set 2 rings the bell based on the calling signal.
When the telephone 2 responds to this ringing by off-hooking, the DC loop is closed and input to the subscriber line switch 1 via the multiplexer B and the multiplexer A as an off-hook signal.
[0025]
Next, the subscriber line switch 1 confirms the response of the telephone 2 and reverses the polarity of the DC loop, and this polarity depolarization signal is input to the telephone 2 via the multiplexer A and the multiplexer B. Then, a call state is entered, and voice transmission (call communication) such as conversation is performed.
[0026]
Next, when the telephone 2 is on-hooked after the end of the call, the DC loop is released, and this on-hook signal is input to the subscriber line switch 1 via the multiplexer B and the multiplexer A, and a series of communication operation sequences is completed. To do.
[0027]
The operation of FIG. 1 will be described based on the above operation sequence.
First, in the transmission side communication path unit 19 provided in the voice compression multiplexing apparatus on the subscriber line switch side, the REP 11 is the polarity inversion of the DC loop, the polarity depolarization signal and the 16 Hz signal output from the subscriber line switch 1. And the like are input to the switching information detection unit 22 and the control signal transmission unit 26.
The voice signal output from the subscriber line switch 1 is input to the voice encoding unit 23 and the caller ID data transmission unit 24 via the hybrid transformer 12. Here, the voice band signal output from the hybrid transformer 12 includes a voice signal for a call and a modem signal for notifying a caller number.
[0028]
The voice signal of the call is voice-compressed by the voice coding unit 23 and coded to 8 kb / s. If the modem signal notifying the caller number is also voice-compressed in the same manner as the voice signal, the modem signal When the modem built in the telephone 2 that receives the signal demodulates the signal, a signal component necessary for demodulation cannot be obtained sufficiently, and a data error cannot be reproduced correctly.
Therefore, although a voice signal for a call is voice-compressed, it is necessary to digitize the modem signal for notifying the caller number so that both signals are distinguished and recognized.
Therefore, the switching information detection unit 22 detects whether or not a modem signal notifying the caller number is transmitted, and recognizes both signals separately. The switching information detection unit 22 detects the modem signal output when notifying the caller number by grasping the operation sequence for notifying the caller number.
[0029]
That is, as explained in FIG. 2, the modem signal (caller number information) for notifying the caller number is output from the subscriber line switch 1 with a polarity inversion of the DC loop and a receiving terminal activation signal of 16 Hz. Since the telephone 2 is sent after the primary response, the switching information detector 22 receives the polarity inversion information output from the subscriber line switch 1 and the receiving terminal activation signal, and then sends the modem signal. Just judge.
[0030]
On the other hand, the stop of the modem signal is determined by detecting the disconnection of the carrier wave signal included in the modem signal, detecting the timeout due to the passage of a predetermined time, or the like.
Accordingly, the switching information detection unit 22 validates the operation of the voice encoding unit 23 that compresses and encodes the call signal, or transmits the caller number data transmission that digitizes the modem signal that notifies the caller number. A switching signal for switching whether to enable the operation of the unit 25 is output.
Then, based on the switching signal from the switching information detection unit 22, when the caller number data transmission unit 24 is activated, the caller number data transmission unit 24 demodulates the modem signal received via the hybrid transformer 12. After obtaining 1200 B data, the 1200 B data is converted to a transmission rate of 8 kb / s and output to the voice / data sending unit 25.
[0031]
On the other hand, when the speech encoding unit 23 is activated based on the switching signal from the switching information detection unit 22, the speech encoding unit 23 samples the analog speech signal received via the hybrid transformer 12 at 8 kHz and outputs 8 By digitizing with bits, a digital signal of 64 kb / s is obtained. Further, the voice encoding unit 23 compresses the digital signal by a predetermined voice encoding method, for example, the CS-ACELP voice encoding method, and outputs it to the voice / data transmission unit 25 as an 8 kb / s digital signal. .
[0032]
Then, in the voice / data transmission unit 25, according to the switching signal output from the switching information detection unit 22, either the voice encoding unit 23 or the digital signal output from the caller ID data transmission unit 24 is selected and multiplexed. To the output.
The control signal transmission unit 26 converts the DC loop polarity signal detected by the REP 11, the receiving terminal activation signal, the detection signal of the 16 Hz signal, and the switching signal output from the switching information detection unit 22 into a predetermined bit string. The data is output to the multiplex conversion unit so as to be put on a predetermined bit (TS1 shown in FIG. 2) of the data frame functioning at a transmission rate of 8 kb / s.
[0033]
Next, in the reception side speech path unit 20 provided in the voice compression multiplexing apparatus on the telephone side, the control signal reception unit 28 of the speech decoding unit 27 receives 8 kb from the signal separated for each speech path by the demultiplexing unit. A predetermined bit (TS1) of a data frame that operates at a transmission rate of / s is extracted, and a control signal such as a DC loop polarity signal, a receiving terminal activation signal, a 16 Hz signal detection signal, and a switching signal are extracted. Then, a switching signal is output to the switching information output unit 29, and a DC loop polarity signal, a receiving terminal activation signal, a 16 Hz signal detection signal, and the like are output to the REP 18.
[0034]
On the other hand, a voice signal from a call or a modem signal notifying a caller number is input from the demultiplexing unit to the voice / data receiving unit 30 at a transmission rate of 8 kb / s.
Each input signal is selected based on the switching signal distributed and output by the switching information output unit 29 by the voice / data receiving unit 30, and the voice signal from the call is sent to the voice decoding unit 31 and the caller number is set. The modem signal to be notified is output to the caller ID data receiving unit 32 separately. Here, the speech decoding unit 31 decompresses the input signal speech-compressed to 8 kb / s and restores it to the original 64 kb / s digital signal. The caller ID data receiving unit 32 restores the 1200B modem data input at a transmission rate of 8 kb / s to a modem carrier signal digitized at 64 kb / s.
[0035]
Next, the voice / data switching unit 33 switches to select either the output of the voice decoding unit 31 or the output of the caller ID data receiving unit 32 according to the switching signal output from the switching information output unit 29. Then, the noise is sequentially output to the noise removing unit 34.
The abnormal sound removing unit 34 removes the abnormal sound generated by dividing and processing the digital signal processing depending on whether it is a voice signal or a modem signal.
Specifically, the switching signal output by the switching information output unit 29 is switched between the digitization processing of the voice signal due to the call, which is the timing of occurrence of the abnormal sound, and the digital signal processing of the modem signal notifying the caller number. The noise is removed by forcing the digital signal input to the noise removing unit 34 to zero for a predetermined time, for example, several hundred msec from the time of the change, to suppress the level.
[0036]
The output of the noise removal unit 34 is input to a D / A conversion unit 35. The D / A conversion unit 35 converts the original analog signal into a two-wire line (subscriber line) via the hybrid transformer 17. Is output to the telephone 2 connected to.
On the other hand, the polarity signal of the DC loop, the receiving terminal activation signal, the detection signal of the 16 Hz signal, and the like for the telephone set 2 are output to the telephone set 2 via the REP 18.
[0037]
As described above, the voice compression and multiplexing apparatus according to the present invention monitors the caller number notification procedure from the subscriber line switch 1 in the voice compression and multiplexing apparatus on the subscriber line switch side so that the voice signal and the modem signal are transmitted. Switching signal is generated, and the switching signal is also multiplexed and transmitted to the audio compression multiplexing device on the opposite side. On the other hand, in the audio compression multiplexing device on the other hand side, abnormal noise is removed based on the switching signal. Therefore, the call quality related to the switching for multiplexing and transmitting the modem signal at the time of caller ID notification is not deteriorated.
[0038]
【The invention's effect】
As described above, according to the present invention, the abnormal sound generated when switching between the digitization processing of the voice signal by the telephone call and the digitization processing of the modem signal for notifying the caller ID is compulsory. Since the digital signal is removed by setting the digital signal to zero, it is possible to exert a great effect on the operation of the voice compression multiplexing apparatus without lowering the speech quality when voice compression multiplexing is performed.
[Brief description of the drawings]
FIG. 1 is an example showing a configuration of a speech path unit of a voice compression multiplexing apparatus according to the present invention, where (a) is a transmission side speech path unit and (b) is a reception side speech path unit.
FIG. 2 is a diagram showing an operation sequence when a caller ID is notified from a subscriber line switch to a telephone through a voice compression and multiplexing device.
FIG. 3 is a diagram illustrating a configuration example of a conventional audio compression multiplexing apparatus.
FIG. 4 is a frame configuration diagram of an audio compression multiplexing apparatus.
[Explanation of symbols]
1. Subscriber line exchanges, 2a, 2b, telephones,
3 .... Voice compression multiplexing equipment on the subscriber line switch side,
4 ・ Voice-side audio compression / multiplexing device,
5a ··· first call path, 5b ··· seventh call path,
6 ・ ・ Multi conversion unit, 7 ・ ・ Demultiplexing unit,
8 .. Demultiplexing part 9 .. Multiple conversion part
10a ··· the first call path section, 10b ··· the seventh call path section,
11. REP (repeater), 12. Hybrid transformer (H),
13 .. Voice encoding part, 14 .. Voice decoding part,
15 .. Speech decoding unit, 16 .... Speech coding unit,
17. ・ Hybrid transformer (H), 18. ・ REP (repeater),
19..Sending-side communication path section, 20.-Receiving-side communication path section,
21 .. Voice encoding part, 22 .. Switching information detection part,
23..Voice encoding unit, 24..Caller ID data transmission unit,
25 .. Voice / data sending part, 26 .. Control signal sending part,
27 .. Voice decoding unit, 28. Control signal receiving unit,
29. ・ Switching information output unit, 30. ・ Voice / data receiving unit,
31 .. Voice decoding unit, 32. Caller ID data receiving unit,
33 .. Voice / data switching part, 34 .. Abnormal sound removal part,
35 ·· D / A converter

Claims (1)

In a voice compression and multiplexing apparatus that is installed opposite to a subscriber line between an exchange and a telephone and compresses and multiplexes voice signals,
The voice compression multiplex device on the exchange side compresses the voice signal from the exchange and encodes it into a digital signal by encoding the voice signal.
A switching information detection unit for detecting whether the voice signal is a modem signal notifying a caller number;
A voice / data transmission unit that selects an output from the voice encoding unit or the caller ID data transmission unit based on the switching signal from the switching information detection unit;
A control signal and a control signal sending unit for encoding the switching signal;
On the other hand, the voice compression multiplexing apparatus on the telephone side has a voice decoding unit that outputs a voice signal that has been decoded into an analog signal to the telephone,
A control signal receiving unit for decoding the control signal and the switching signal;
A voice / data receiving unit that distributes the received signal to a voice decoding unit or a caller ID data receiving unit based on the decoded control signal;
A voice / data switching unit that selects an output from the voice decoding unit or the caller ID data receiving unit based on the decoded control signal;
Based on the decoded control signal, an allophone removing unit that suppresses allophone generated at the time of switching by the voice / data switching unit;
And a D / A converter for converting the digital signal from the abnormal noise removing unit into an analog signal.

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