JPH06216860A - Voice communication equipment - Google Patents

Abstract

PURPOSE:To provide a voice communication equipment which never transfers the useless voice codes in a silent state and can assure the talking with no sense of incompatibility. CONSTITUTION:A digital voice decoder 17 decodes the voice codes supplied from a transmission line decoder 16 for each frame, and the digital voice signals are sent to an adder 19. If the absence of the voice code is reported based on the voice presence information supplied from the decoder 16, no voice signal to be transmitted is confirmed. Thus the level of the voice code supplied precedently by one frame is sent to a noise generator 18. When the absence of the voice code is reported in the preceding way, the generator 18 outputs a noise signal of a level equivalent to the voice level supplied from the decoder 17 to the adder 19. Then the noise signal is transmitted to a voice processing circuit, etc., which are excluded out of the diagram.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice communication device,
More specifically, the present invention relates to a voice communication device that communicates voice information by digital voice compression.

[0002]

2. Description of the Related Art Recently, with the development of an advanced information society, demand for a communication medium for transmitting / receiving a large amount of information at high speed has increased, and ISDN (Integrated Services Digital) has been used as a communication system corresponding to this communication demand. Network:
A digital communication network such as a service integrated digital network) has been put into practical use, and a digital telephone device or the like has been developed and put into practical use as a communication terminal connected to this digital communication network.

A digital telephone device connected to a conventional digital communication network has a communication function of encoding and transmitting / receiving voice information. Regarding the encoding method, CC is used.
It is stipulated for each type of communication network according to ITT (International Telegraph and Telephone Consultative Committee) recommendations and the like. Further, in the conventional digital telephone device, it is known that the delay of the voice signal has a great influence on the progress of the conversation. Therefore, an ordinary digital telephone apparatus accompanied by digital voice compression can compress the average generated bit length, but generally applies entropy compression (for example, Huffman coding) in which the maximum bit length is not guaranteed to a voice signal. I can't. The reason is that if a voice signal is generated to have a long bit length by entropy compression, a large transmission delay occurs in the voice signal, which seriously affects conversation. That is, the audio signal is encoded and transmitted with a fixed bit length in the conventional videophone device and videoconference system.

Specifically, the conventional speech coding apparatus is configured as shown in the block diagram of FIG.

In FIG. 5, a voice encoding device 1 converts an input digital voice signal into an AD-PCM (Adaptive Dif).
ferential PCM) method or CELP (Code-Excite)
d L-inear Predivtion) or other fixed-length coding scheme, and outputs the speech code to the transmission channel encoder 3, and the speech input from the digital speech encoder 2. By the transmission path encoder 3 that performs operations such as rearranging the bitstreams and generating error correction codes when the codes are actually sent to the transmission path, and sends the codes to the transmission path (not shown) as a transmission path code. It is configured.

A conventional speech decoding apparatus is constructed as shown in the block diagram of FIG.

In FIG. 6, a voice decoding device 6 generates a voice code by performing processing such as rearranging bit streams and error correction on a transmission path code transmitted by the voice encoding device 1 of FIG. Channel decoder 7 for outputting to a digital voice decoder 8 and a digital voice for decoding a voice code input from the channel decoder 7 and outputting a digital voice signal to a voice processing circuit (not shown) or the like. It is composed of a decoder 8.

Further, in such a conventional digital telephone device, it is rare that two callers from both parties speak at the same time. That is, half of the transmitted and received digital audio data is considered to be silent.
In such a silent state during a call, the number of bits assigned to voice data is transmitted as "silent" data.

[0009]

However, in such a conventional digital telephone device, the number of bits assigned to the voice data in the silent state during a call is as follows.
Since the "silent" data is transmitted as it is, there is a problem that the data area allocated to the voice data is wasted.

Also, when a silent state occurs during a call, the user is sent as "silent" data, so that the user feels that the connection line with the other party's digital telephone device is disconnected, and there is no sound during the call. There was also a problem that the state made the user feel uncomfortable.

An object of the present invention is to provide a voice communication device capable of making a call without feeling uncomfortable without transferring useless voice codes in a silent state.

[0012]

The means of the present invention are as follows.

According to the present invention, digital voice information is encoded, a voice code encoded according to a predetermined procedure is transmitted through a transmission line, and a voice code received through the transmission line is decoded. A voice communication device for processing has a detection unit for detecting the presence / absence of digital voice information to be encoded / decoded, and a noise generation unit for generating a predetermined noise, and the detection / encoding is performed by the detection unit. When it is detected that there is no digital voice information to be processed, the transmitting side does not transmit the voice code, and the receiving side causes the noise generating means to generate noise.

[0014]

The operation of the means of the present invention is as follows.

According to the present invention, the digital voice information is encoded, the voice code encoded according to a predetermined procedure is transmitted through the transmission line, and the voice code received through the transmission line is received. In the audio communication device for decoding processing, when the detecting means detects that there is no digital audio information for encoding / decoding processing, no audio code is transmitted on the transmitting side and a predetermined noise is generated from the noise generating means on the receiving side. Noise is generated.

Therefore, it is possible to eliminate the waste of transmitting a silent voice code, and when the voice is silent, a predetermined noise is generated to recognize that the call is in progress, and the call can be continued without a feeling of strangeness.

[0017]

EXAMPLES Examples will be described below with reference to FIGS.

1 to 4 are views showing an embodiment of a digital telephone device to which the voice communication device of the present invention is applied.

First, the structure will be described. FIG. 1 is a block diagram of a voice encoding device 10 provided in the digital telephone device of this embodiment.
It is a block configuration diagram of. In this figure, a speech coder 10 comprises a digital speech coder 11 and a transmission line coder 12.

The digital voice encoder 11 converts an input digital voice signal into an AD-PCM (Adaptive Different).
ial PCM) or CELP (Code-Excited Lin)
The audio code is output to the transmission path encoder 12, the presence or absence of the input digital audio signal is detected, and the detection result is transmitted by the audio presence information. It is output to the path encoder 12.

The transmission path encoder 12 performs operations such as rearranging bit streams and generating error correction codes when the speech code input from the digital speech encoder 11 is actually transmitted to the transmission path. In addition, the header information is transmitted to a transmission line (not shown) as a transmission line code in units of one frame, and header information for notifying the presence / absence of a voice code is generated according to the voice presence information input from the digital voice encoder 11, The road code is added at the time of transmission.

Here, an example of the data structure of a voice code generated in the voice encoding device 10 and transmitted / received via a transmission line between the transmitting side digital telephone device and the receiving side digital telephone device is shown in FIG. Shown in.

FIG. 2 shows voice codes alternately transmitted / received by the digital telephone devices on the transmitting side and the receiving side on a frame-by-frame basis. In each frame, the transmission line encoder 12 of FIG. A voice header is added before the voice code by the processing, and the presence or absence of the voice code is detected by both the transmitting side and the receiving side by transmitting and receiving this voice header.

For example, when the user's voice is interrupted on the transmitting side and becomes silent, as shown in FIG. 3, the frame on the transmitting side is processed by the channel encoder 12 of FIG. An unvoiced header is added and no voice code is sent to the transmission line. That is, in this embodiment, when the voice is interrupted during the call, the voiceless code is notified by adding the unvoiced header.

FIG. 4 is a block diagram of a voice decoding device 15 provided in the digital telephone device of this embodiment. In this figure, a speech decoding device 15 is composed of a transmission channel decoder 16, a digital speech decoder 17, a noise generator 18 and an adder 19.

The transmission channel decoder 16 performs processing such as bitstream rearrangement and error correction on a transmission channel code transmitted from the speech encoding apparatus 10 shown in FIG. 1 via a transmission channel (not shown). When a voice code is generated and output to the digital voice decoder 17, a voiceless header is added to the header of the data received for each frame. Notify the decoder 17 and the noise generator 18.

The digital voice decoder 17 decodes the voice code input from the transmission line decoder 16 and outputs a digital voice signal to the adder 19, and the voice input from the transmission line decoder 16 as well. If the presence information indicates that there is no voice code, there is no voice signal to be output, and the voice level of the voice code input one frame before is output to the noise generator 18.

The noise generator 18, when notified by the voice presence information input from the transmission line decoder 16 that there is no voice code, has the same noise level as the voice level input from the digital voice decoder 17. The signal is output to the adder 19.

It should be noted that the noise generator 21 has a noise signal equivalent to that of the audio signal one processing unit before so as not to make the user feel uncomfortable during a call when there is no audio code. Is provided to eliminate the feeling of strangeness during a call.

The adder 19 is a digital speech decoder 17
The digital audio signal input from the or the noise signal input from the noise generator 18 is output to an audio processing circuit (not shown) or the like.

Next, the operation of this embodiment will be described.

First, the operation of the voice encoding device 10 during a call in the digital telephone device will be described.

In FIG. 1, when a digital audio signal is input to the digital audio encoder 11 in the audio encoding device 10 by an audio processing circuit (not shown) or the like, the digital audio signal is converted into a digital audio encoder 11. Is encoded by a fixed-length encoding method based on the AD-PCM method or CELP method, and is output to the transmission path encoder 12 as a voice code.

At this time, the digital voice encoder 11 detects the presence or absence of the input digital voice signal, and the detection result is notified to the transmission line encoder 12 by the voice presence information. When the transmission line encoder 12 is notified by the voice presence information that there is a voice code, rearrangement of bit streams and generation of error correction codes when actually transmitting to the transmission line, as shown in FIG. 2 above. As described above, the voice header is generated, added to the voice code, and the transmission line code is sent to the transmission line via the communication processing circuit (not shown).

Next, the operation of the voice decoding device 15 during a call in the videophone device will be described.

In FIG. 4, when an audio bit stream is input to the transmission path decoder 16 in the audio decoding device 15 via a communication control circuit (not shown), the audio bit stream is subjected to transmission path decoding. The converter 16 performs rearrangement of bit streams, error correction, etc. to generate a voice code and outputs it to the digital voice decoder 17, and adds a voiceless header to the header of data received for each frame. If so, the digital voice decoder 17 and the noise generator 18 are notified by the voice presence information that there is no voice code.

In the digital speech decoder 17, the speech code input from the transmission channel decoder 16 in units of one frame is decoded, the digital speech signal is output to the adder 19, and the transmission channel decoder is also provided. If it is notified by the voice presence information that is input from 16 that there is no voice code, there is no voice signal to be output, and therefore the voice level of the voice code that was input one frame before is the noise generator 18.
Is output to.

At this time, in the noise generator 18,
The voice presence information input from the transmission line decoder 16 notifies that there is no voice code, and a noise signal having the same level as the voice level input from the digital voice decoder 17 is output to the adder 19. . In the adder 19, the digital audio signal input from the digital audio decoder 17 or the noise signal input from the noise generator 18 is output to an audio processing circuit (not shown) or the like.

As described above, in the digital telephone device of this embodiment, the voice encoding device 10 detects the presence / absence of voice during a call, and when a voiceless state occurs, the voice code is not transmitted and the voice is not voiced. A header is added to notify the receiving side video telephone device that there is no voice. When the videophone device is notified that there is no voice code during a call, the noise generator 18 outputs a noise sound equivalent to the voice code received in the previous frame in order to avoid a silent state by the voice decoding device 15. To be done.

Therefore, it is possible to avoid the transmission of the number of transmission bits, which has been wasted by the silence code during a call in the past, and the silent state generated during a call causes a noise sound to the user. It is possible to recognize that the call is continuing and eliminate discomfort during the call.

In the above embodiment, when the silent state occurs, the noise sound is generated by the noise generator 18. However, for example, environmental noise around the digital telephone device is generated. You may make it recognize that it is talking on the phone.

Needless to say, the communication system is not limited to the above embodiment.

[0043]

According to the present invention, when the detecting means detects that there is no digital voice information to be encoded / decoded, the voice code is not transmitted on the transmitting side, and the noise generating means determines on the receiving side. Since it is configured to generate the noise of, it is possible to eliminate the waste of transmitting a silent voice code,
When there is no sound, a predetermined noise is generated to recognize that the call is in progress, and the call can be continued without a feeling of strangeness.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a voice encoding device in a digital telephone device to which a voice communication device of the present invention is applied.

2 is a data configuration diagram of an audio bitstream output by the audio encoding device in FIG. 1 when there is an audio code.

FIG. 3 is a data configuration diagram of an audio bit stream output by the audio encoding device in FIG. 1 when there is no audio code.

FIG. 4 is a block configuration diagram of a voice decoding device in a digital telephone device to which the voice communication device of the invention is applied.

FIG. 5 is a block configuration diagram of a voice encoding device in a conventional voice communication device.

FIG. 6 is a block configuration diagram of a voice decoding device in a conventional voice communication device.

[Explanation of symbols]

 10 Speech Coding Device 11 Digital Speech Encoder 12 Channel Encoder 15 Speech Decoding Device 16 Channel Decoder 17 Digital Speech Decoder 18 Noise Generator 19 Adder

Claims (1)

[Claims] 1. Digital audio information is encoded, a voice code encoded according to a predetermined procedure is transmitted via a transmission line, and a voice code received via the transmission line is decoded. A voice communication device, comprising: detection means for detecting the presence / absence of digital voice information to be encoded / decoded; and noise generation means for generating a predetermined noise, wherein the detection / encoding processing is performed by the detection means. A voice communication device, characterized in that, when it is detected that there is no digital voice information, the transmitting side does not transmit a voice code and the receiving side generates noise from the noise generating means.