JP2002016572A - Voice compression multiplexer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a voice compression multiplexer that transmits no abnormal noise sound to a telephone set, in the case of digital processing. SOLUTION: A transmitter side speech channel section 19 is provided with an REP 11 that relays a control signal, a hybrid transformer 12 that conducts two-wire/four-wire conversion, and a voice-coding section 21 that applies voice compression to a voice signal to encode it with the control signal, and the voice-coding section 21 is provided with a switching information detection section 22, a voice-coding section 23, a caller number data transmission section 24, a voice/data transmission section 25 and a control signal transmission section 26. A reception speech channel section 20 is provided with a voice-decoding section 27 that decodes the voice signal and the control signal, a hybrid transformer 17 that conducts four-wire/two-wire conversion, and an REP 18 that relays the control signal. A voice decoding section 27 is provided with a control signal reception section 28, a switching information output section 29, a voice/ data receiving section 30, a voice-decoding section 31, a caller number data receiving section 32, a voice/data changeover section 33, an abnormal noise sound eliminating section 34 and a digital/analog converter section 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice compression multiplexing apparatus, and more particularly, to a digital line by installing means between a telephone line exchange and a telephone set and taking means for voice compression and coding of a voice signal. The present invention relates to an audio compression and multiplexing apparatus capable of suppressing a transmission band when a plurality of audio lines are multiplexed and transmitted using the same.

[0002]

2. Description of the Related Art Conventionally, audio signals are multiplexed by compressing and encoding audio signals as much as possible, and a means for improving line efficiency, which is important for communication, is often used. As for the subscriber line, a voice compression multiplexing device for voice-compressing and coding a voice signal for multiplexing a communication path between a subscriber line exchange and a telephone has been introduced.

FIG. 3 is a diagram showing a configuration example of a conventional audio compression / multiplexing apparatus. FIG. 1 shows an example in which a voice exchange multiplexing device 3 for a local line exchange and a voice compression multiplexing device 4 for a telephone side are installed between the local exchange 1 and the telephones 2a and 2b. . That is, in this example, seven subscriber lines between the subscriber line exchange 1 and the telephone set 2 are connected to the subscriber line exchange side voice compression multiplexing apparatus 3 and the telephone side voice compression multiplexing apparatus 4. Between them, transmission and reception are performed by multiplexing them on a pair of transmission paths.

[0004] The voice compression multiplexing apparatus 3 for the subscriber line exchange comprises a first communication path section 5a to a seventh communication path for compressing and encoding a voice signal and decompressing and decoding a voice signal. Unit 5b, a multiplex conversion unit 6 for multiplexing the seven communication paths from the first communication path unit 5a to the seventh communication path unit 5b, and a multiplexed signal from the telephone side voice compression / multiplexing unit 4. And a demultiplexing unit 7 for separating the separated signals. On the other hand, the voice compression multiplexing device 4 on the telephone side, like the voice compression multiplexing device 3 on the local line exchange side, includes a demultiplexing unit 8, a multiplex conversion unit 9, and first communication path units 10a to 10a. And a seventh communication path section 10b.

The first communication path unit 5a includes a REP (repeater) 11 for relaying control signals input / output to / from the subscriber line exchange 1, and a two-wire line (subscriber) connected to the subscriber line exchange 1. ), A hybrid transformer (H) 12 for converting the audio signal into a four-wire system, an audio encoding unit 13 for compressing the audio signal and encoding it together with the control signal, and decoding the encoded audio signal and control signal. And an audio decoding unit 14 that performs the decoding. This configuration is the same up to the seventh communication path section 5b.
The first communication path unit 10a is provided with the first communication path unit 5a.
Similarly to the above, a voice decoding unit 15 for decoding the coded voice signal and the control signal, a voice coding unit 16 for voice-compressing the voice signal and coding it together with the control signal, and a two-wire Hybrid transformer (H) 17 for converting to a line
And a REP for relaying a control signal input / output to / from the telephone 2a.
18.

The operation of FIG. 3 will be described. In the figure, seven communication paths (subscriber lines) connected to the subscriber line switch 1 are connected to the voice compression multiplexing device 3 on the side of the subscriber line exchange, and seven telephones 2 are compressed and multiplexed on the side of the telephone line. The voice compression multiplexing device 3 on the subscriber line exchange side receives the voice signal from the subscriber line exchange 1, and the voice compression multiplexing device 4 on the telephone side transmits the voice signal from the telephone set 2. The signal is, for example, 8 kb / s using the CS-ACELP speech coding scheme.
s, multiplex and transmit. Here, an example is shown in which the voice compression multiplexing device 3 on the subscriber line exchange side and the voice compression multiplexing device 4 on the telephone side are connected via a 64 kb / s digital line.

First, a case where a call is received from the local exchange 1 to the telephone set 2a will be described. The 16 Hz calling signal output from the local exchange 1 and the polarity information of the DC signal are transmitted to the first communication path section 5a. Detected by the provided REP 11 and input to the voice encoding unit 13. The audio signal is converted from a two-wire system to a four-wire system by the hybrid transformer 12, and a voice signal from the subscriber line exchange 1 is input to the voice encoder 13.

[0008] In the speech encoding unit 13, the speech signal is 8
The audio is compressed to kb / s and encoded, and output to the multiplex conversion unit 6, and the 16 Hz calling signal and the polarity information of the DC signal are input to the multiplex conversion unit 6 as control bits. Next, the multiplex conversion unit 6 multiplexes the compressed digital audio signals of the seven communication paths, and converts the multiplexed signal into a 64 kb signal.
The data is transmitted to the voice compression multiplexing apparatus 4 for the telephone side via the digital line of / s.

In the voice compression multiplexing apparatus 4 for the telephone set, the received multiplexed signal is demultiplexed by the demultiplexing section 8 for each communication path, and the separated compressed digital voice signal is corresponded for each communication path. Communication path section 10a to seventh communication path section 10b
To enter. In the first communication path unit 10a, the audio decoding unit 1
5, the audio signal and the control signal for the telephone 2 are decoded into an analog signal, and the audio signal is
7 is output to the telephone 2a via the REP 18 as a control signal.

On the other hand, a case where a signal is transmitted from the telephone set 2a will be described. R provided in part 10a
The signal is detected by the EP 18 and input to the speech encoding unit 16.
The audio signal from the telephone set 2 a is converted from a two-wire line to a four-wire line by the hybrid transformer 17 and output to the voice encoder 17. In the speech encoding unit 17,
The analog audio signal is voice-compressed and encoded into a digital signal of 8 kb / s and input to the multiplex conversion unit 9.
An intermittent signal such as a loop signal of a DC circuit or a dial pulse is input to the multiplex conversion unit 9 as a control bit.

Next, the multiplex conversion section 9 converts the multiplexed signal obtained by multiplexing the compressed digital audio signals of the seven communication paths into 64 multiplexed signals.
The data is transmitted to the voice compression multiplexing device 3 on the subscriber line exchange side via a kb / s digital line. The voice compression multiplexing apparatus 3 for the subscriber line exchange separates the received multiplexed signal for each communication path by the demultiplexing section 7, and separates the separated compressed digital voice signal from the first communication path section 5a to the seventh communication path. Call path 5
Input to b. In the first communication path section 5a, the audio decoding section 1
4 decodes a voice signal and a control signal for the local exchange 1 into an analog signal, and outputs the voice signal to the hybrid transformer 12 and the control signal to the local exchange 1 via the REP 11.

In recent years, a telephone switching network has been provided with a caller ID notification service (number display), and the above-mentioned conventional voice compression / multiplexing apparatus requires a caller ID notification function. There is. The above-described caller ID notification service is a service that, when an incoming call is received from the local exchange 1 to the telephone 2, the telephone 2 notifies the caller of the caller before responding to the incoming call. Before calling the telephone 2, the caller ID is notified from the local exchange 1 to the telephone 2 by a modem signal of 1200B (baud rate) according to a predetermined procedure.

However, when this modem signal is compressed to 8 kb / s by the above-mentioned voice compression multiplexing apparatus and transmitted, when the modem signal is received on the telephone side, the necessary band component cannot be sufficiently received and the modem signal cannot be received. A bit error occurs during demodulation of. Therefore, the modem signal used for the caller ID notification function needs to demodulate the modem signal into 1200B data, convert it to a signal having a transmission speed of 8 kb / s without compressing the voice, and output the signal. Therefore, the voice encoding unit that performs the voice compression process identifies whether the input voice signal is a voice signal from a telephone call or a modem signal notifying the caller ID. The circuit is switched to perform dedicated digitization processing, and the identification for this switching is as follows:
The modem signal may be specified by identifying an operation sequence determined for the caller ID notification function.

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 line by the audio compression multiplexing apparatus that multiplexes seven communication channels. This frame is a control slot (TS1) composed of control signals for seven communication paths, synchronization bits, and the like.
And seven main signal slots (TS2 to TS8) of seven communication paths including a voice compression signal or a modem signal.
The transmission rate is 64 kb / s by transmitting one 4-bit frame in 1 msec. The bit sequence (d) constituting the main signal has no 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. A signal is created, and the bit sequence (d) constituting the main signal is synchronized with the timing signal. Note that the main signal shown in the above-mentioned bit string (d) has 80 bits of 10 m.
The transmission speed is 8 kb / s by transmitting in sec. Therefore, as a method of synchronizing the main signal with the timing signal at 10 msec intervals based on the synchronization bit included in the control slot, first, as shown in FIG.
Generate a multi-frame composed of frames,
As shown in (a), a multi-frame is generated by 6 multi-frames, and a multi-frame of 30 msec is generated.
This is performed by synchronizing the above-mentioned 10 msec timing signal with the head of this multi-frame.

[0015]

However, the conventional audio compression / multiplexing apparatus has the following problems. That is, in the speech encoding unit 13, when the operation of identifying the modem signal and switching the speech compression process to the digitization process of the modem signal, and the operation of restoring, the speech compression process and the modem signal digitization process are performed separately. The switching operation and the recovery operation are performed asynchronously irrespective of the frame synchronization functioning to recognize the bit position in the frame generated by the multiplex conversion unit 6. Specifically, in the voice encoding unit and the voice decoding unit, the operation of identifying the modem signal and switching the voice compression process to the digitization process of the modem signal, and the recovery operation are performed asynchronously with the 10 msec timing signal. , Frame synchronization is lost. As a result, an operation error occurs in the audio decoding unit 15 until the multiplex conversion unit 6 establishes the frame synchronization again, and an abnormal sound is transmitted to the telephone set 2 to lower the communication quality.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is an object of the present invention to provide a method of transmitting a caller ID without deteriorating call quality involved in switching for multiplexing and transmitting a modem signal at the time of caller ID notification. It is an object of the present invention to provide a voice compression multiplexing device that can support a notification service.

[0017]

SUMMARY OF THE INVENTION To achieve the above object, a voice compression multiplexing apparatus according to the present invention is installed opposite a subscriber line between an exchange and a telephone to multiplex voice signals by voice compression. In the voice compression multiplexing device, the voice compression multiplexing device on the exchange side converts the voice signal from the exchange into a digital signal by voice-compressing and coding the voice signal. A switching information detecting unit for detecting whether or not the modem signal is to be notified; and a voice / voice for selecting an output from a voice encoding unit or a caller ID data transmitting unit based on a switching signal from the switching information detecting unit. A data transmission unit and a control signal transmission unit for encoding the control signal and the switching signal are provided. On the other hand, the audio compression multiplexing device on the telephone side outputs the decoded audio signal to the telephone. A control signal receiving unit that decodes the control signal and the switching signal; and a sound that distributes the received signal to a voice decoding unit or a caller ID data receiving unit based on the decoded control signal. A data / data receiving unit, a voice / data switching unit that selects an output from the voice decoding unit or the caller number data receiving unit based on the decoded control signal, and a voice / data switching unit based on the decoded control signal. An abnormal sound removing unit that suppresses abnormal sound generated at the time of switching by the voice / data switching unit; and a D / D converter that converts a digital signal from the abnormal sound removing unit into an analog signal.
A conversion unit is provided. For this reason, at the time of the switching when the modem signal notifying the caller number is received and at the time of recovery, the abnormal sound removing unit forcibly sets the level of the audio signal to zero for a predetermined time. This can prevent the quality of the call to the telephone from deteriorating.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments. FIG. 1 is an embodiment showing a configuration of a communication path section of a voice compression multiplexing apparatus according to the present invention.
Although not shown, the local exchange 1
In addition, it is assumed that the voice compression multiplexing device 3 for the subscriber line exchange and the voice compression multiplexing device 4 for the telephone line are installed opposite to each other between the plurality of telephones 2, and the transmission side communication path shown in FIG. The section 19 is provided in the voice compression multiplexing apparatus 3 on the subscriber line exchange side, and the receiving side communication path section 20 shown in (b) is provided in the voice compression multiplexing apparatus 4 on the telephone side. Here, in order to explain the operation related to the caller ID notification function from the local exchange 1, the description of the functional blocks relating to the call direction from the telephone set 2 to the local exchange 1 will be omitted.

FIG. 1 shows the configuration of the transmitting side communication path 19.
A REP (repeater) 11 for relaying control signals input / output to / from the subscriber line exchange 1 and a two-wire line (subscriber line) connected to the subscriber line exchange 1 Transformer (H) that converts to a 4-wire circuit
12 and a voice coding unit 21 for voice-compressing a voice signal from the local exchange 1 and coding it together with a control signal. Then, based on the control signal detected by the REP 11, the voice encoding unit 21 determines whether the input signal from the local exchange 1 is a voice signal for a telephone call or a modem signal for notifying a caller number. And a switching information detecting unit 22 for outputting a switching signal for switching the audio coding processing method, and digitizing the analog audio signal from the hybrid transformer 12 to 64 kb / s.
Speech encoder 23 for compressing and encoding speech at 8 kb / s
After demodulating the modem signal for notifying the caller number from the hybrid transformer 12 to 1200B data,
A caller number data transmitting unit 24 that outputs at a transmission rate of kb / s, and an output from the voice encoding unit 23 and a caller number data transmitting unit based on control of a switching signal output by the switching information detecting unit 22. 24, a voice / data transmission unit 25 for switching to select one of the outputs from the transmission unit 24 and transmitting it to the multiplex conversion unit; A signal transmitting unit 26 is provided.

On the other hand, the receiving communication path section 20 includes a voice decoding section 27 for decoding the encoded compressed voice signal or the caller ID data and the control signal, and converts a four-wire system into a two-wire system. And a REP 18 for relaying a control signal input / output to / from the telephone 2. The audio 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. Unit 28 and a switching signal from the control signal receiving unit,
A switching information output unit 29 for distribution to a data receiving unit 30, a voice / data switching unit 33, and an abnormal sound removing unit 34, and a modem for notifying a voice signal or a caller number separated for each communication path by a demultiplexing unit A voice / data receiving unit 30 that receives a signal and outputs a voice signal to a voice decoding unit 31 and a modem signal to a caller number data receiving unit 32 based on the switching signal from the switching information output unit 29; , The voice /
An audio decoding unit 31 for decompressing an audio signal compressed to 8 kb / s input from the data receiving unit 30 and decoding it into an original digital signal of 64 kb / s; The input 1200B caller ID data converted to the input 8 kb / s transmission rate is converted to 6
A caller number data receiving unit 32 that converts the data into a modem modulated wave digitized at 4 kb / s, and an output from the voice decoding unit 31 and a caller number data reception based on the control of the switching signal from the switching information output unit 29 A voice / data switching unit 33 for switching and outputting any one of the outputs from the unit 32; a decompressed 64 kb / s digital voice signal and a 64 kb / s digital modem signal for notifying the caller number. An abnormal sound elimination unit 34 for eliminating noise generated at the time of switching output and a D / A conversion unit 35 for converting a digital signal into an original analog signal are provided.

Next, the operation sequence of the caller ID notifying function required for modem signal identification in the switching information detecting section 22 of the voice encoding section 21 will be described. FIG. 2 is a diagram showing an operation sequence when notifying the telephone number from the local exchange 1 to the telephone 2 via the voice compression multiplexing devices 3 and 4. The operation sequence shown in this figure starts when a call is received from the local exchange 1 to the telephone set 2. In other words, the local exchange 1 first inverts the polarity of the DC power supplied to the subscriber line to the voice compression and multiplexing apparatus 3 (hereinafter referred to as the multiplexing apparatus A) for the local exchange. At the same time, a 16 Hz signal is turned on for 0.5 sec as a receiving terminal start signal for starting the telephone 2,
Outputs intermittently at 0.5 sec OFF.

The polarity inversion signal and the receiving terminal start signal are
The signal is input to the telephone 2 via the multiplexing device A and the voice compression multiplexing device 4 for the telephone side (hereinafter, referred to as the multiplexing device B), and the telephone 2 receives a direct current as a primary response to the polarity inversion signal and the receiving terminal activation signal. Close the loop. Then, when the primary response signal from the telephone set 2 is input to the local exchange 1 via the multiplexer B and the multiplexer A, the local exchange 1 transmits 1200B to notify the caller ID.
, And outputs a modem signal (caller ID information) according to a predetermined data format by a start-stop synchronization method.

Next, the modem signal from the local 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. And a DC loop is opened as a reception completion signal. When the reception completion signal from the telephone 2 is input to the local exchange 1 via the multiplexer B and the multiplexer A, the local exchange 1 generates a call signal for calling the telephone 2. 16 Hz for 1 second
It outputs cON and 2secOFF intermittently.

Next, the call signal from the local exchange 1 is
The signal is input to the telephone 2 via the multiplexing device A and the multiplexing device B, and the telephone 2 rings the bell based on the ringing signal. When the telephone 2 responds to this ringing by going off-hook, the DC loop is closed and the signal is input to the subscriber line exchange 1 via the multiplexer B and the multiplexer A as an off-hook signal.

Next, the local exchange 1 confirms the response of the telephone set 2 and reverses the polarity of the DC loop. The polarity reversal signal is transmitted to the telephone set 2 via the multiplexer A and the multiplexer B.
Is entered, a call state is entered, and voice transmission (call communication) such as conversation is performed.

Next, when the telephone 2 is on-hook after the end of the call, the DC loop is released, and this on-hook signal is transmitted through the multiplexer B and the multiplexer A to the local exchange 1
And a series of communication operation sequences ends.

The operation of FIG. 1 will be described on the premise of the above operation sequence. First, in the transmission side communication path section 19 provided in the voice compression multiplexing device on the side of the subscriber line exchange, the REP 11 is used for reversing the polarity of the DC loop outputted from the subscriber line exchange 1, reversing the polarity, and outputting the 16 Hz signal. And the like, and the detection signal is input to the switching information detection unit 22 and the control signal transmission unit 26. The voice signal output from the local exchange 1 is transmitted via the hybrid transformer 12 to the voice encoder 23 and the caller ID data transmitter 24.
Is input to Here, the voice band signal output from the hybrid transformer 12 includes a voice signal from a telephone call and a modem signal for notifying a caller number.

The voice signal generated by the call is converted into a voice signal by the voice coding unit 23.
Is compressed to 8 kb / s, and if the modem signal for notifying the caller ID is also subjected to voice compression in the same manner as the voice signal, the modem built in the telephone 2 receiving the modem signal is When the signal is demodulated, sufficient signal components required for the demodulation cannot be obtained, resulting in a data error and an incorrect reproduction. Therefore, it is necessary to compress the voice signal of the telephone call, but to digitize the modem signal for notifying the caller number so that the modem signal is dedicated to the modem signal and recognize the two signals separately. Therefore, the switching information detection unit 22 detects whether or not a modem signal for notifying the caller number is transmitted, and recognizes both signals separately. The switching information detecting unit 22 detects a modem signal output when notifying the caller number by grasping an operation sequence for notifying the caller number.

That is, as described with reference to FIG.
A modem signal (caller number information) for notifying the caller number outputs a receiving terminal start signal consisting of a DC loop polarity inversion and 16 Hz from the subscriber line exchange 1, and after the telephone 2 makes a primary response thereto, Since it is transmitted, the switching information detection unit 22 may determine that the modem signal is transmitted after receiving the polarity inversion information and the receiving terminal start signal output from the local exchange 1.

On the other hand, the suspension of the modem signal is determined by detecting the interruption of the carrier signal included in the modem signal, detecting the timeout after a predetermined time has elapsed, and the like. Therefore, the switching information detecting unit 22 enables the operation of the voice encoding unit 23 for voice-compressing and encoding the call signal, or transmits the caller number data for digitizing the modem signal for notifying 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 operation of the caller number data transmission unit 24 becomes valid, the caller number data transmission unit 24 demodulates the modem signal received via the hybrid transformer 12. After obtaining 1200B data, this 1200B
The data of B is converted to a transmission speed of 8 kb / s and output to the audio / data transmission unit 25.

On the other hand, based on the switching signal from the switching information detecting unit 22, when the operation of the audio encoding unit 23 becomes effective, the audio encoding unit 23 samples the analog audio signal received via the hybrid transformer 12 at 8 kHz. Then, the data is digitized by 8 bits to obtain a 64 kb / s digital signal. Further, the audio encoding unit 23 converts the digital signal into a predetermined audio encoding method, for example, C
8k compressed by S-ACELP audio coding
voice / data transmission unit 25 as a b / s digital signal
Output to

The voice / data transmitting section 25 selects one of the digital signals output from the voice encoding section 23 or the caller number data transmitting section 24 in accordance with the switching signal output from the switching information detecting section 22. And outputs it to the multiplex converter. The control signal sending unit 26 receives a DC loop polarity signal detected by the REP 11, a receiving terminal start signal, 16 Hz
The signal detection signal and the like and the switching signal output from the switching information detection unit 22 are encoded so as to be converted into a predetermined bit sequence, and the predetermined bits of a data frame functioning at a transmission rate of 8 kb / s (FIG. Is output to the multiplex conversion unit so as to be loaded on TS1) shown in FIG.

Next, in the receiving side communication path unit 20 provided in the voice compression multiplexing apparatus on the telephone side, the voice decoding unit 27
The control signal receiving unit 28 extracts a predetermined bit (TS1) of a data frame operating at a transmission rate of 8 kb / s from the signal separated for each communication path by the demultiplexing unit.
A control signal such as a polarity signal of a DC loop, a reception terminal start signal, a detection signal of a 16 Hz signal, and a switching signal are extracted. Then, a switching signal is output to the switching information output unit 29, and a polarity signal of the DC loop, a receiving terminal start signal, a 16 Hz signal detection signal, and the like are output to the REP 18.

On the other hand, a voice signal from a call or a modem signal for notifying a caller number is sent from the demultiplexer at 8 kb / s.
Is input to the voice / data receiving unit 30 at a transmission speed of. Each of the input signals is selected by the voice / data receiving unit 30 based on the switching signal distributed and output by the switching information output unit 29, and the voice signal from the call is sent to the voice decoding unit 31.
Further, the modem signal for notifying the caller number is output separately to the caller number data receiving section 32. Here, the voice decoding unit 31 decompresses the input signal voice-compressed to 8 kb / s and restores the original 64 kb / s digital signal. The caller number data receiving unit 32 converts the 1200B modem data input at a transmission rate of 8 kb / s into 64 bytes.
Restore to a modem carrier signal digitized at kb / s.

Next, the voice / data switching unit 33 selects 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. And sequentially output to the abnormal noise removing unit 34. The abnormal noise removing unit 34 eliminates abnormal noise generated by dividing and processing the digital signal processing according to whether the signal is a voice signal or a modem signal. More specifically, the switching signal output by the switching information output unit 29 is switched when the switching between the digitization processing of the voice signal due to the telephone call, which is the timing at which abnormal noise occurs, and the digital signal processing of the modem signal for notifying the caller number. The noise is eliminated by forcibly setting the digital signal input to the abnormal noise removing unit 34 to zero and suppressing the level for a predetermined time, for example, several hundred msec from the point of change.

The output of the abnormal noise removing section 34 is output from the D / A converting section 3.
5, the D / A converter 35 converts the signal into an original analog signal, and then outputs the signal to the telephone 2 connected to a two-wire line (subscriber line) via the hybrid transformer 17. 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 2 are output to the telephone 2 via the REP 18.

As described above, the voice compression multiplexing apparatus according to the present invention monitors the caller ID notification procedure from the subscriber line exchange 1 in the voice exchange multiplexing apparatus on the side of the local exchange, and outputs the voice signal. And a switching signal for distinguishing between a modem signal and a modem signal. The switching signal is also multiplexed and sent to the voice compression multiplexing device on the opposite side. Since the apparatus is configured to perform abnormal noise removal, the quality of communication related to switching for multiplex transmission of a modem signal at the time of notification of a caller ID does not decrease.

[0038]

As described above, according to the present invention, the abnormal sound generated when switching between the digitizing process of the voice signal by the telephone call and the digitizing process of the modem signal for notifying the caller ID is generated by generating the abnormal sound. The digital signal is removed by forcibly reducing it to zero for a certain period of time, so that the speech compression multiplexing does not degrade the communication quality and has a great effect on the operation of the voice compression multiplexing device. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a configuration of a communication path unit of an audio compression / multiplexing apparatus according to the present invention, wherein (a) shows a transmission-side communication path unit;
(B) is a receiving side communication path unit.

FIG. 2 is a diagram showing an operation sequence when notifying a telephone number from a subscriber line exchange to a telephone set via a voice compression multiplexing apparatus.

FIG. 3 is a diagram illustrating a configuration example of a conventional audio compression / multiplexing apparatus.

FIG. 4 is a diagram illustrating a frame configuration of an audio compression / multiplexing apparatus.

[Explanation of symbols]

1 ... Subscriber line exchange, 2a, 2b ...
Telephone, 3... Voice compression multiplexing device on the subscriber line exchange side, 4... Voice compression multiplexing device on the telephone side, 5 a... First communication path portion, 5 b. ..Multiplexing section, 7 Multiplexing section, 8 Multiplexing section, 9
..Multiple conversion section, 10a first communication path section
10b 7th speech path section, 11 REP (repeater), 12 hybrid transformer (H), 13 voice code section 14
..Speech decoding unit, 15
16. Voice coding unit, 17 Hybrid transformer (H), 18 REP (repeater), 19 Transmission channel unit, 20 Communication channel unit on reception, 21 Voice code unit, 22・ ・
Switching information detecting section, 23... Voice coding section,
24: Caller ID data transmission unit, 25: Voice /
Data transmission unit, 26 control signal transmission unit, 2
7 voice decoding unit 28 control signal receiving unit 29 switching information output unit 3
0: voice / data receiving unit, 31: voice decoding unit,
32 ... caller number data receiving section, 33
..Voice / data switching section, 34..Noise removal section, 35.D / A conversion section

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[Procedure amendment]

[Submission date] June 30, 2000 (2006.3.3)
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Claims (1)

[Claims] An audio compression multiplexing apparatus installed opposite to a subscriber line between an exchange and a telephone to compress and multiplex an audio signal by voice, wherein the voice compression multiplexing apparatus on the side of the exchange comprises a voice from the exchange. A switching information detecting unit that detects whether or not the voice signal is a modem signal for notifying a caller ID; A voice / data transmitting unit that selects an output from a voice encoding unit or a caller number data transmitting unit based on a switching signal from the unit; and a control signal transmitting unit that encodes a control signal and the switching signal. On the other hand, the voice compression and multiplexing device on the telephone side receives a control signal for decoding the control signal and the switching signal by a voice decoding unit that outputs the decoded voice signal to the telephone. A voice / data receiving unit for distributing a received signal to a voice decoding unit or a caller ID data receiving unit based on the decoded control signal; and the voice decoding based on the decoded control signal. A voice / data switching unit for selecting an output from a unit or a caller ID data receiving unit; and an allophone canceling unit for suppressing an abnormal noise generated at the time of switching by the voice / data switching unit based on the decoded control signal. And a D / A converter for converting a digital signal from the abnormal sound remover into an analog signal.