JPH0621900A - Silence suppression variable controller for voice signal - Google Patents

Abstract

PURPOSE:To properly discriminate between voice and silence by allowing the user to revise a threshold level optionally even during communication so as to use a parameter operated simply such as a power level. CONSTITUTION:A silence, suppression controller processing a data block as a packet when a sender side discriminates a voiced sound and aborting the data in the case of silence is provided with a threshold table 9 for a parameter used for discrimination, and means 16, 11, 10, 8 or the like revising and deciding the threshold level optionally with an external command. In the case of discrimination, the threshold level table 9 is used. Thus, the user.user information of D-channel in, e.g. an existing interface is used and control information is sent to an opposite terminal equipment even during communication to revise the threshold level table of the opposite party.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silence suppression control device for packetized voice, and more particularly to a voice silence suppression variable control device which allows a user to change a threshold value for determining whether sound is present or not even during communication.

[0002]

2. Description of the Related Art Speech contains a lot of silence between words, between speeches, etc. Therefore, if the silence is removed and only the voiced portion is sent out as a packet, the transmission efficiency is improved. Can be significantly improved. In order to realize it, there is a need for technology that can minimize the communication processing and correctly maintain the silent section length for reproduction. As a method thereof, there is a method in which the packet length is fixed, it is determined whether there is voice or silence in the unit of length, and what is determined as the voice is packetized. In this method, first, the input voice sequence is stored for the packet length, and at the same time, the parameter calculation for determining the presence of voice, for example, power calculation is performed, and when the data for the packet length is stored, the voice for the length is stored. Based on the calculation result of the parameter with respect to the data, it is determined whether there is sound or no sound. By doing so, the silence suppression processing can be performed only with the normal accumulation time, and the processing time can be minimized. Further, since the length of the voiced section and the length of the voiceless section are all integral multiples of the packet length (fixed length), for example, by assigning a sequence number to each packet, the length of the voiceless section can be maintained very easily. . The above method
This is a very effective method that can be directly applied to ATM (fixed-length packet is called a cell), which is the basic technology of B-ISDN. However, in order to determine the performance of the above method, it is important not only to shorten the processing time and to simplify the processing, but also to improve the accuracy of the sound / silence determination itself. for that reason,
As a method to improve the judgment performance without increasing the processing time,
For example, the following method can be considered. (1) A plurality of types of parameters are used instead of one type of parameter used for voice detection. For example, the number of zero crossings or the like is obtained without determining only the loudness of the sound based on the power, and the feature of the voice can be extracted more. (2) Prepare multiple values for the parameter judgment threshold,
Comprehensive control by state. For example, different thresholds may be used for the transition from the voiced state to the silenced state and vice versa. (3) A hangover time is provided to prevent the ending of the word. However, even with the above method, there is a limit to the improvement in performance, and since the threshold value of the parameter is basically fixed,
In particular, it is difficult to flexibly respond to changes in call status. For example, the level differs for each call due to the influence of the terminal or its anameg subscriber system, and in some cases, the level is transmitted at a very low level, and it may be determined that all of the calls are silent. Also,
In order to extract the voice feature more accurately, it is necessary to calculate a complicated parameter, which increases the processing time. Note that Japanese Patent Application No. 64-69 is an example of a packet transmission system using silence suppression.

[0003]

In the above-mentioned prior art, since the determination threshold value such as the power level is fixed, there is a problem that the determination quality itself changes if the state of the level etc. is different for each call. . An object of the present invention is to improve such a problem by allowing the user to arbitrarily change the determination threshold value even during communication, and to use a parameter that can be easily calculated, such as a power level, and to use a voice It is an object of the present invention to provide a voice silence suppression variable control device capable of more appropriately determining silence.

[0004]

In order to achieve the above object, the judgment threshold value itself is made variable, and even a voice having a power level that is judged to be silent in one call is judged to be voice in another call. You can set it as follows. In addition, if the user who is actually listening to the control of the setting (instruction as to whether to increase or decrease) is performed,
It should be optimally controlled. Therefore, the voice silence suppression variable control device of the present invention determines whether the digital coded sequence is voiced or voiceless for each data block unit of the data length defined in the communication procedure, and generates a packet when voiced. And a means for transmitting the packet (a packet generation determination circuit, a packetization processing circuit, etc.) and a means for receiving the transmitted packet, decomposing it according to the contents of the header, and restoring it to the original digital coded sequence (packet reproducing circuit, etc.). ), The data block is packetized when it is determined to be voiced by the transmitting side, and when it is determined that the data block is not voiced, the voice redundancy compression communication system discards the data block. Table that stores the threshold value of the parameter used when determining the threshold value (threshold table), and the threshold value can be arbitrarily changed / determined by external instructions. Stage (parameter input circuit, peer receiver parameter changing circuit,
It is characterized in that a value stored in a threshold value table is used for the above determination in the case of the above-mentioned determination.

[0005]

In the present invention, when the presence / absence of a packet is determined by using the presence / absence determination, the packet generation determination circuit reads and uses the threshold value of the control parameter stored in the threshold value table. Further, the control parameter determination circuit determines a threshold value and rewrites the threshold value table in accordance with a change request arbitrarily input / instructed from the outside. Among these change requests, the change request from the user (own side) to the other side (reception side) is made into a cell in a format determined between terminals as a decision threshold value change request signal via the other party transmission parameter change circuit. (Hereinafter, this processing is called message conversion) and transmitted. For example, if the user information of the D channel in the existing interface is used,
Control information can be transmitted to the partner terminal even during communication. On the other hand, on the receiving side, the judgment threshold value change request signal is extracted, the judgment threshold value to be actually changed is translated from the contents by the other party reception parameter change circuit, and the control parameter decision circuit judges the value of its own device. Write to the threshold table. By such an operation, the caller (or the receiver) can set a desired parameter value after confirming the call state for each call. That is, the calling side user or the called side user can arbitrarily change the threshold for packet generation determination to mutually change the voice quality. Further, by expanding this, not only the sound / silence detection determination in the packet generation determination but also the general quality can be variably controlled.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a silence suppression variable control device according to an embodiment of the present invention. In the voice redundancy compression communication system of the present embodiment, a digital coded sequence such as voice is stored in fixed-length data block units, and it is determined whether or not there is voice in each data block unit, and when it is determined that there is voice. Packetizes the data block and transmits it, and when it is determined that there is no sound, the data block is not packetized and only the sound part is transmitted. At this time, the time stamp is added to each input data block in order regardless of the packet generation determination, and the receiving side determines that the packet section is a silent section when a missing number is detected based on the sequence of the received packet. , Play a voice with the same silent section length as the original voice. FIG. 1 shows the configuration of a device that performs this silence suppression control. In FIG. 1, 1 is linear or μ_
A signal input terminal based on the LAWPCM code, 2 is an arithmetic circuit for performing an arithmetic operation (control of signal power and zero-crossing) regarding a control parameter that uses a signal periodically input from the terminal 1 for packet generation determination, and 3 is an arithmetic circuit. The packet generation determination circuit 4 for determining whether to generate a packet based on the operation result of 2 stores the input voice information until a specified time, and a timing buffer 5 for guaranteeing the timing of packet generation determination. Is a packetization processing circuit for giving packet processing and information (sequence number (time stamp) or the like) for displaying the contents of the data block unit, 6 is a memory for storing the output of the packetization processing circuit 5, and 7 is A transmission circuit for reading out the coded sequence stored in the memory 6, adding a header or the like, and transmitting it to the line side, 8 is a parameter A control parameter value determination circuit for determining a packet generation determination threshold value determined by the correlation of some parameter values input from the input circuit 16, and 9 is composed of a RAM and gates for controlling its access, A threshold value table for storing the threshold value determined by the control parameter value determining circuit 8, 10 is a partner transmission parameter changing circuit, 11 is a partner receiving parameter changing circuit, 12 is a receiving circuit for receiving and disassembling packets, 13 Is a memory for storing the received packet data, 14 is a time stamp monitoring circuit for monitoring the arrival order of the received packets, and 15 is for generating the received packets in the original digital sequence, and a silent pattern or an appropriate pattern during the silent period. A packet reproducing circuit having a function of generating various noises, and 16 is an interface with a terminal 17. That the parameter value input circuit, 17 is a terminal for inputting a value of the control parameters used by the packet generation determining circuit 3 from the outside. In addition, the threshold table 9 has a conflict control circuit that controls the conflict between writing when changing the threshold and reading when determining the packet generation. This is composed of gates and the like, and when a write / read conflict occurs between the packet generation determination circuit 3 and the control parameter value determination circuit 8, the access right from the packet generation determination circuit 3 is given priority, and It has a function to change the threshold value after the generation judgment is completed. As a result, even if the threshold value for packet generation determination is changed during communication, the influence on communication due to the change is eliminated. When determining whether or not to generate a packet, the packet generation determination circuit 3 reads the value in the threshold table 9 and compares the value with the calculation result in the calculation circuit 2. Then, the determination result is displayed on the packetization processing circuit 5 as a signal with generation or a signal without generation.

Here, the operation of the transmitting side will be described. With such a configuration, for example, a signal input from the input terminal 1 at a cycle of 125 μs is subjected to arithmetic operations such as voice power and zero crossing as control parameters for each packet generation determination in the arithmetic circuit 2 and simultaneously input to the timing buffer 4. Then, a delay corresponding to the determined period is given and input to the packetization processing circuit 5. The packetization processing circuit 5 performs necessary processing on the input data (for example, encoding processing) and sequentially writes it in the memory 6. In this case, assuming that the packetization period is 6 ms, at the time when 48 samples are input, the arithmetic circuit 2 transmits the power addition result of the 48 samples and the zero crossing aggregation result to the packet generation determination circuit 3, The packet generation determination circuit 3 compares the calculation result with the respective parameter values read from the threshold value table 9 to determine the presence or absence of packet generation. As a result, when it is determined that there is no packet generation, the packetization processing circuit 5 receives the display of the non-generation signal of the packet generation determination circuit 3 by checking the timing between the last sample having 48 sample values and the next sample. , The data block is not packetized. Further, when the packet is generated, the packetization processing circuit 5 causes the packet generation determination circuit 3 to
Is generated, the samples of the data block are continuously stored in the memory 6, packet processing is performed at the time when 48 samples are accumulated, and the transmission circuit 7 is instructed to transmit the corresponding packet. . On the other hand, the packetization processing circuit 5 counts the time stamps indicating the packet order for each data block regardless of the packet generation determination. Add to the stamp,
No transmission instruction is given to the transmission circuit 7. Therefore, the packetized data block is discarded. After that, when the next data block is continuously transmitted (sound determination), it is given from the time stamp next to the previously counted data block, packetized, and transmitted. This is for notifying the packet reproducing circuit 15 of the time length of silence suppression using a time stamp. In addition, when the user changes the control parameter value for packet generation determination at the start of communication or during communication, those signals are input from terminal 17 to change the control parameter for packet generation determination on the local side or the other side. Then, it is received by the parameter input circuit 16. When the content of the change is on its own side, the control parameter value determination circuit 8 determines the threshold value for packet generation determination and writes the value in the threshold value table 9. As a result, the packet generation determination circuit 3 reads the threshold value table at the time of determination, and determines the presence or absence of packet generation according to the threshold value. On the other hand, when a signal for changing the control parameter value of the packet generation determination circuit on the other side is input from the terminal 17, the parameter input circuit 16 first receives it and informs the control parameter determination circuit 8 as a partner side change request signal, The value of the control parameter is passed to the control parameter determination circuit 8. The control parameter determination circuit 8 passes the parameter value as it is to the partner transmission parameter modification circuit 10 in response to the partner modification request signal. The partner transmission parameter changing circuit 10 converts the content into a message (for example, using the user / user information of the control information channel (D channel) in ISDN or the like) and stores it in the memory 6 according to the protocol (packet transmitting means). It is stored and the transmission circuit 7 transmits it. As a result, it is possible to control the packet generation determination of the other party.

Next, the operation of the receiving side will be described. The receiving circuit 12 performs a receiving process according to the communication protocol and stores the received packet in the memory 13. on the other hand,
The time stamp monitoring circuit 14 monitors the continuity of the received packets and, if they are continuous, sends the packet data as they are to the packet reproducing circuit 15, and if they are discontinuous, the time stamps of the received packets and the current received packet are received. The difference between the time stamps is calculated, and the time length corresponding to the number of the differences is set as the time during which silence is suppressed or lost, and the data is not transferred to the packet reproduction circuit 15 by the time length. It monitors packet fluctuation delays and drops,
This is because the packet processing circuit 5 and the packet reproduction circuit 15 are synchronized so that the packet reproduction circuit 15 can accurately reproduce the original voice without time distortion. Further, during the silent section length, the packet reproducing circuit 15 generates and outputs a silent pattern or appropriate noise. Also,
When a packet with a judgment threshold value change request signal is received at the receiving side at the start of communication or during a call, the destination of the packet is sorted by the header information, the packet is stored in the memory 13, and the receiving parameter of the other party is changed. The circuit 11 extracts the content of the packet and sends the determination threshold value change request signal to the control parameter value determination circuit 8. The control parameter value determination circuit 8 writes the threshold value for packet generation determination in the threshold value table 9. As a result, the other party can control the voice quality to the optimum (desired) call state.

Next, a communication form between terminals will be described by taking a network system in which a plurality of terminals are connected via an ATM network using the silence suppression variable control device described in FIG. 1 as an example. 2 and 3 are configuration diagrams of a network system using the silence suppression variable control device of the present invention. 2 and 3, reference numeral 21 denotes a terminal A, 2 connected to the ATM network 23 via a terminal adapter 22.
Reference numeral 5 is a terminal B connected to the ATM network 23 via the terminal adapter 24, 22 is a terminal adapter (TA-1) for controlling silence suppression of voice, 24 is a terminal adapter (TA-2), and 23 is a plurality of terminals. ATM to connect
This is a network, and this terminal adapter has the same function as the silence suppression variable control device shown in FIG. That is, the cell determining units 221 and 241 correspond to the packet generation determining circuit 3, and the cell assembling / disassembling units (CLAD) 222 and 242 are
It corresponds to the arithmetic circuit 2, the timing buffer 4, the packetization processing circuit 5, the time stamp monitoring circuit 14, and the packet reproducing circuit 15. Also, the transmitting / receiving units 223, 2
The transmitting unit 43 corresponds to the memory 6 and the transmitting circuit 7,
The receiving unit corresponds to the receiving circuit 12 and the memory 13.
Further, the parameter input units 220a and 240a in the control units 220 and 240 correspond to the parameter input circuit 16, and the control parameter input terminals 211 and 251 are the terminals 17.
Corresponding to. Also, the threshold value determining units 220b and 240b
Corresponds to the control parameter determination circuit 8 and the threshold table 9. In addition, the partner transmission changing units 220c and 240
c corresponds to the partner transmission parameter changing circuit 10, and the partner reception changing units 220d and 240d correspond to the partner receiving parameter changing circuit 11. In this embodiment, the terminal 21 is in communication.
When the user inputs the local side change signal and the control parameter value from the input terminal 211 of the terminal 21 in order to further change the control parameter value for silence suppression, the value is received by the parameter input unit 220a in the TA-2, The value is transferred to the threshold value determination unit 220b. The threshold value determining unit 220b determines a threshold value for cell generation determination (silence suppression) based on the control parameter value, and writes the threshold value in a threshold value table in the threshold value determining unit 220b. On the other hand, the cell generation determining unit 221 refers to the threshold table at the time when data is accumulated in the determined data block unit, determines the packet generation, and notifies the cell assembling / disassembling unit 222 of the result. To do. Cell assembly / disassembly section 222
If the determination result indicates that the data block has been generated, the data block is converted into a cell, passed to the transmission / reception unit 223, and transmitted.
If not generated, discard and do not send. Further, when changing the control parameter value of the cell generation determination, which is the determination threshold for silence suppression on the partner (TA-2) side,
The network 23 uses a signal system (out-band signal system) in which a signal channel and an information channel are separated, and similarly transfers user information between terminals. As a result, the terminal 2
When the partner side change signal and its control parameter value are input from the input terminal 211 in No. 1, the parameter input unit 220a of TA-1 receives them and the control parameter value received by the partner side judgment threshold value change request signal. To the other party's transmission changing unit 220c via the threshold value determining unit 220b.
Pass to. The partner transmission change circuit 220c converts the content into a message and causes the transmission / reception unit 223 to transmit the message.
At the other party (reception side) TA-2, the other party reception change unit 240d receives the cell in the form of a message, interprets the contents, and passes the control parameter value to the threshold value determination unit 240b. Change the control parameter value for cell generation determination.

[0010]

According to the present invention, the silence suppression technique is used for packet generation determination, the value of the control parameter is input from the outside, and the threshold value for packet generation determination is controlled to make a call at the user's discretion. Since the packet generation determination threshold can be variably set for each call or during a call, the user can select the optimum quality according to the contents of voice information to be transmitted and the call state. Further, by expanding the present invention, it is possible to variably control general quality in addition to the presence / absence detection of sound in the packet generation determination.

[0011]

[Brief description of drawings]

FIG. 1 is a configuration diagram of a silence suppression variable control device according to an embodiment of the present invention.

FIG. 2 is a part of a configuration diagram of a network system using the silence suppression variable control device of the present invention.

FIG. 3 is a part of a configuration diagram of a network system using the silence suppression variable control device of the present invention.

[Explanation of symbols]

 1 terminal 2 arithmetic circuit 3 packet generation determination circuit 4 timing buffer 5 packetization processing circuit 6 memory 7 transmission circuit 8 control parameter value determination circuit 9 threshold table 10 partner transmission parameter change circuit 11 partner reception parameter change circuit 12 reception circuit 13 Memory 14 Time stamp monitoring circuit 15 Packet reproducing circuit 16 Parameter input circuit 17 Terminal 21 Terminal A 22 Terminal adapter (TA-1) 23 ATM network 24 Terminal adapter (TA-2) 25 Terminal B 211 Control parameter input terminal 220 Control section 221 Cell determination unit 222 Cell assembly / disassembly unit (CLAD) 223 Transmission / reception unit 220a Parameter input unit 220b Threshold value determination unit 220c Other party transmission change unit 220d Other party reception change unit 240 Control unit 241 Cell determination unit 42 cell assembly and disassembly unit (CLAD) 243 transmit and receive unit 240a parameter input unit 240b threshold determining unit 240c mating transmission changing unit 240d peer receiver changing section 251 controls the parameter input terminal

Claims (1)

[Claims] 1. A means for determining, for each data block having a data length defined by a communication procedure, whether or not a digital coded sequence has voice, and if there is voice, means for generating and transmitting a packet, and said means. The packet transmitted from is received, decomposed according to the contents of the header, and means for restoring the original digital coded sequence is provided, and when it is determined that there is sound on the transmission side,
When the data block is packetized and transmitted, and when it is determined that there is no sound, in the voice redundancy compression communication system that discards the data block, the threshold value of the parameter used when determining whether there is sound or no sound is set. A threshold value stored in the table is used at the time of the above determination, provided with a table to be stored and means for arbitrarily changing / determining the threshold value according to an instruction from the outside. Silence suppression variable control device.