JP2003298644A - Voice communication system, method for communicating voice, transmission system and reception system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow a synchronization to be facilitated at a reception side. <P>SOLUTION: In a transmission system 10, when a silence is detected, a synchronous packet is transmitted instead of a packet for a normal comfort noise. A reception system 20 demodulates a reception signal, and takes a frame synchronization by using a frame synchronous signal in a radio header and a synchronous packet in a voice signal. The reception system replaces the synchronous packet with a silent packet for controlling to generate the comfort noise, and generates the comfort noise by using the silent packet. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a voice communication system and method.

[0002]

2. Description of the Related Art Generally, in a system for encoding and transmitting voice, a voice signal is divided every 20 msec, and a voice waveform parameter in each section is analyzed and transmitted.
The receiving side reproduces the audio signal based on the parameter. Further, in a specific system, when the voice signal is silent in one section, the parameter of the confocal noise generated on the receiving side is transmitted, and the confocal noise is generated on the receiving side based on the parameter. To do. As a result, even if a silent state occurs during a conversation, it is possible to prevent the speaker from mistakenly recognizing that the communication is interrupted.

In such a system, in order for the receiving side to correctly recognize each parameter, it is necessary to correctly establish frame synchronization with the transmitting side. Therefore, normally, a frame synchronization signal is inserted at the start of communication so that the receiving side performs the synchronization process.

[0004]

However, if the frame synchronization processing is performed only at the start of communication as described above, if the reception is started in the middle of communication, the synchronization processing cannot be performed at all. Further, once the frame synchronization is lost due to a failure of the communication path due to fading or the like, it is impossible to reestablish the frame synchronization. Therefore, if the frame synchronization signal is inserted at the beginning of each voice packet, the transmission efficiency is reduced by that much.

To solve these problems, Japanese Patent Laid-Open No. 60-287
There is a technique described in Japanese Patent Publication No. 00. According to this, when the voice signal is silent or silent, the one that does not need to be transmitted among the parameters that characterize the voice waveform.
Since (for example, a parameter indicating a spectrum envelope) exists, the portion can be replaced with a frame synchronization signal and transmitted, whereby the frame synchronization can be reestablished on the receiving side without lowering the transmission efficiency.

However, in the above-mentioned specific system, the parameter of the comfort noise generated at the receiving side is transmitted instead of the parameter of the voice signal when there is no sound. Even if there is, there is no parameter that is not particularly necessary. Further, in the technique disclosed in Japanese Patent Laid-Open No. 60-28700, only a part of the parameters in the voice packet is replaced with the frame sync signal, so that the length of the frame sync signal must be limited. As a result, the reliability of the synchronization process on the receiving side becomes low.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to facilitate synchronization on the receiving side. Another object of the present invention is to enable frame synchronization processing without reducing transmission efficiency. Another object of the present invention is to enable comfortable wireless communication.

[0008]

To achieve the above object, a voice communication system according to a first aspect of the present invention comprises:
On the transmitting side, the input voice signal is divided at regular intervals to detect whether the voice signal in each section is voiced or silent, and when it is voiced, the voice waveform in that section is characterized. Analyzing a parameter to be attached, and transmitting a voiced packet including the parameter as a voice packet,
When there is no sound, a soundless packet containing the parameters of the comfort noise generated by the receiving side is transmitted as a voice packet, and when the received voice packet is a voiced packet, the voice signal is transmitted according to the parameter included in the voice packet. When the voice packet to be transmitted is a silent packet at the transmitting side, the voice communication system is configured to generate conform noise when the voice packet is a silent packet. A packet is transmitted by replacing it with a synchronization packet composed of a frame synchronization signal, the reception side continuously monitors the reception signal, and when the synchronization packet is detected, a frame synchronization process is performed. , Generated the detected sync packet separately Characterized in that it has to replace the similar manner silence packets.

According to this structure, the receiving side can achieve frame synchronization by using the voice packet. Moreover, as in the conventional case, it is possible to generate comfort noise when there is no sound.

In order to achieve the above object, a voice communication system according to a second aspect of the present invention has
The input voice signal is divided at regular intervals to detect whether the voice signal in each section is voiced or silent,
When there is a voice, a parameter that characterizes the voice waveform in the section is analyzed, and a voice packet including the parameter is transmitted as a voice packet, and when there is no voice, a parameter of the comfort auto noise generated on the receiving side. When a voice packet received by the receiving side is a voice packet, the voice signal is reproduced according to the parameter included in the voice packet, and when the voice packet is a voice packet, according to the parameter included in the voice packet. In a voice communication system that generates comfort noise, when a voice packet to be transmitted is a silent packet on the transmitting side, the silent packet is replaced with a preset specific silent packet and then transmitted. The received signal on the receiving side. Monitored it continued, and when the specific silence packet is detected, and to perform the frame synchronization process, and wherein the.

Also with this configuration, it becomes possible for the receiving side to establish frame synchronization by using the voice packet.
Moreover, as in the conventional case, it is possible to generate comfort noise when there is no sound.

In order to achieve the above object, a voice communication system according to a third aspect of the present invention has
Detecting whether the input audio signal is voiced or silent, when it is voiced, a voiced packet is transmitted, and when it is not voiced, a predetermined packet is transmitted, and at the receiving side,
When the received voice packet is a voice packet, the voice signal is reproduced, and when the voice packet is a predetermined packet, synchronization is taken and conform noise is output based on the predetermined packet.

On the transmitting side, when the input voice signal is silent, a synchronous packet is transmitted as the predetermined packet, and on the receiving side, the received signal is monitored, and when the synchronous packet is detected, the frame synchronous processing is carried out. In addition to the above, the detected synchronization packet may be replaced with a packet including a comfort noise parameter, and comfort noise may be generated according to the replaced packet.

On the transmitting side, when the input voice signal is silent, a packet containing fixed parameters is transmitted,
On the receiving side, when monitoring a received signal and detecting a packet containing the fixed parameter, frame synchronization processing is performed and comfort noise is generated according to the parameter stored in the detected packet containing the fixed parameter. Good.

In order to achieve the above-mentioned object, a transmission system according to a fourth aspect of the present invention has an input means for inputting a voice signal and dividing the voice signal at regular intervals, and the voice signal in each section is voiced. It detects whether it is silent or not, and outputs a voiced packet containing information for reproducing an audio signal when it is voiced, and when it is not voiced, it includes a parameter of the confocal noise generated on the receiving side. A vocoder that outputs a silent packet, a replacement unit that determines the type of packet output by the vocoder, and replaces a silent packet with a predetermined synchronization packet, and a voice packet and a synchronization packet that is replaced by the replacement unit And a control unit for generating a transmission frame by adding a header.

In order to achieve the above-mentioned object, a transmission system according to a fifth aspect of the present invention has an input means for inputting a voice signal and dividing the voice signal at regular intervals, and the voice signal in each section is voiced. It detects whether it is silent or not, and when it is sound, it outputs a sound packet containing information for reproducing the audio signal, and when it is silent, it outputs a sound packet containing the parameter of confauto noise on the receiving side. A vocoder to output, a silent packet output from the vocoder is replaced with a packet of a specific pattern that enables frame synchronization by the synchronization detection circuit on the receiving side, and a packet of the replaced specific pattern and a voice packet from the vocoder A control means for generating a transmission frame by adding a wireless header, a means for wirelessly transmitting the generated transmission frame,
Equipped with.

In order to achieve the above-mentioned object, a transmission system according to a sixth aspect of the present invention has an input means for inputting a voice signal and dividing the voice signal at regular intervals, and the voice signal in each section is voiced. It detects whether it is silent or not, and outputs a voiced packet containing information for reproducing an audio signal when it is voiced, and when it is not voiced, it includes the parameter of the receiving side's confauto noise and the receiving side. Means for outputting a silent packet of a specific pattern to enable frame synchronization by the synchronization detection circuit of (1), a wireless header is added to the voiced packet and the silent packet, a transmission frame is generated, and the generated transmission frame is wirelessly transmitted. And means for doing so.

In order to achieve the above object, a reception system according to a seventh aspect of the present invention receives a radio frame including a radio header including a frame synchronization signal and a plurality of voice packets following the radio header. Receiving means for demodulating, a synchronization detecting means for detecting frame synchronization based on a frame synchronization signal in the radio frame demodulated by the receiving means and a specific packet in the voice packet, and Generating means for reproducing voice based on a packet other than the specific packet and generating comfort noise based on the specific packet.

A specific packet in the voice packet is
For example, it is composed of a synchronization packet. The synchronization detection means comprises means for replacing the synchronization packet with a silent packet including a parameter for generating comfort noise, and the generation means outputs voice based on a packet other than the specific packet in the voice packet. A vocoder for reproducing and generating comfort noise based on the silent packet is provided.

To achieve the above object, a receiving system according to an eighth aspect of the present invention receives a radio frame including a radio header containing a frame synchronization signal and a plurality of voice packets following the radio header. Receiving means for demodulating the received data, synchronization detecting means for detecting frame synchronization based on a frame synchronization signal in the wireless frame demodulated by the receiving means, and a packet of a specific pattern in the voice packet; A vocoder that reproduces voice based on a packet other than the specific packet and that generates a noise signal of comfort noise using information included in the packet of the specific pattern as a parameter.

In order to achieve the above-mentioned object, a voice communication method according to a ninth aspect of the present invention is a voice communication method for wirelessly transmitting voice from a transmitting side to a receiving side. Regarding the voice signal of the target voice, a packet signal containing voice data is transmitted, and in the silent state, a synchronization packet is transmitted, and on the receiving side, frame synchronization is performed using the synchronization packet. Is characterized by reproducing voice, and further generating and outputting comfort noise based on the synchronization packet.

In order to achieve the above object, a voice communication method according to a tenth aspect of the present invention detects whether an input voice signal is voiced or silent, and when it is voiced,
A voice packet for playing voice is transmitted, and when there is no sound, a fixed packet containing a fixed parameter of confauto noise on the receiving side is transmitted, and the voice packet received on the receiving side is a voice packet. Sometimes
The audio signal is reproduced, and when it is a fixed packet, synchronization with the fixed packet is performed, and comfort noise is generated and output using a fixed parameter in the fixed packet.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION A voice communication system according to an embodiment of the present invention will be described below with reference to the drawings. <First Embodiment> FIG. 1 is a block diagram showing a configuration of a voice communication system according to a first embodiment of the present invention.

As shown in FIG. 1, this voice communication system comprises a transmission system 10 and a reception system 20. Note that, in FIG. 1, the transmission system 10 and the reception system 20 are illustrated as separate bodies for easy understanding, but each terminal device includes a transmission system 10 and a reception system 2.
Of course, it is possible to configure so as to include 0 and.

In this system, the sound picked up by the microphone of the transmission system 10 is transmitted to the reception system 20 and reproduced from the speaker. The transmission frame of the signal transmitted from the transmission system 10 to the reception system 20 is
As shown in FIG. 1, it is composed of a wireless header including a bit synchronization signal, a frame synchronization signal, and header information, and a repeating signal of a voice packet following the wireless header.

Conventionally, a comfort noise voice packet was transmitted in the silent state, but in this embodiment, as shown in FIG. 1, a synchronization packet is inserted in place of the comfort noise voice packet. It is possible to establish synchronization in the receiving system 20.

The transmission system 10, as shown in FIG.
Microphone 11, A / D converter 13, and vocoder 15
And a control circuit 17 and an RF unit 19.

The microphone 11 detects voice and outputs a corresponding analog electric signal.

A / D (Analog to Digital) converter 1
3 samples an analog signal output from the microphone 11 at a predetermined sampling period, and outputs a digital signal (PC
M signal). More specifically, the A / D converter 13 samples the input analog audio signal at a sampling cycle of 16 bits and 8 kHz and converts it into 16 bits of PCM data. The A / D converter 13
The generated PCM signal is sequentially output to the vocoder 15 serially (16-bit parallel) in 16-bit units.

The vocoder 15 is composed of, for example, an AMDE series vocoder IC sold by DVSI, etc., detects a PCM signal from the A / D converter 13, and if a voice exists, the PCM signal is detected. Is compressed into voice packets for a predetermined period of time, and when voice is not present, comfort noise packets are combined, and a control packet containing control information indicating the presence or absence of voice and dummy data are added to these. It is provided to the control circuit 17.

More specifically, the vocoder 15
Functionally, as shown in FIG.
A silent packet generator 153, a controller 155, and a synthesizer 157.

Under control of the control unit 155, the encoder 151 performs an encoding process for each 160 samples (16 bits × 160) of the PCM data output from the A / D converter 13 to generate a 48-bit voice packet.
Encoding time interval is 1/8 kHz x 16
0 = 20 ms.

The silence packet generator 153 generates a 48-bit voice packet including a 6-bit header indicating a comfort noise packet and 42-bit data including noise volume and spectrum information. Hereinafter, in order to distinguish a normal voice packet including voice picked up by the microphone 11 and a voice packet including comfort noise information, they are referred to as voiced packets and silence packets, respectively, and are collectively referred to as voice packets. And

The control unit 155 analyzes the PCM data from the A / D converter 13 and detects a silent state due to breathing or breaks in words. The control unit 155 outputs an operation enable signal to the encoder 151 at the timing of detecting a voiced state (not a silence state), and outputs an operation enable signal to the silence packet generation unit 153 when the silence state is detected.

The control unit 155 also generates a 192-bit control packet containing various control information and 144-bit dummy data. The control packet includes a silence flag indicating whether or not it is in a silence state.
The control unit 155 turns on this silence flag when it is detected that it is in a silent state.

Under the control of the control circuit 155, the synthesizing unit 157 controls the control packet (silence flag off) at the timing when the control circuit 155 detects the voiced state.
The voice packet from the encoder 151 and the dummy data are combined to generate 384-bit data, which is output to the control circuit 17. On the other hand, the synthesizing unit 157 controls the control unit 155.
At the timing when the silence state is detected, the control packet (silence flag ON), the silence packet and the dummy data are combined to generate 384-bit data, which is output to the control circuit 17.

The control circuit 17 includes a processor and a DSP (Di
The vocoder 1 is composed of a digital signal processor, etc.
Among the data from 5, the silence packet is replaced with a predetermined synchronization packet, and a radio header is added to the beginning of the transmission to perform RF.
Send data to unit 19.

More specifically, the control circuit 17
Functionally, as shown in FIG. 2, the separation unit 171, the interpretation unit 173, the synchronization packet generation unit 175, and the replacement unit 1
77 and a wireless header adding unit 179.

The separating unit 171 is provided with the 38 from the vocoder 15.
The 4-bit data is divided into control data, voice packet (voice packet or voiceless packet), and dummy data, and the control packet is provided to the interpretation unit 173.
The voice packet is provided to the replacement unit 177. Interpreting unit 173
Discriminates the silence flag of the control packet provided from the separating unit 171, discriminates whether the provided voice packet is a voice packet or a silent packet, and sends the control signal indicating the discrimination result to the replacing unit 177. Output.

The synchronization packet generator 175 generates a synchronization packet.

When the voice packet is a silent packet, the replacing unit 177 replaces the silent packet with the synchronous packet from the synchronous packet generating unit 175 and outputs the silent packet according to the control signal from the interpreting unit 173.

The wireless header adding unit 179 adds a wireless header at the beginning of transmission, then repeatedly outputs a voice packet or a synchronization packet, and adds an end packet at the end of a transmission frame. As described above, the wireless header includes a 64-bit bit synchronization signal, a 15-bit frame synchronization signal, and 272-bit header information.

The RF unit 19 shown in FIG. 1 generates an IQ signal in accordance with the transmission data, orthogonally transforms the IQ signal, and GM.
Generate an SK signal. Then, this signal is mixed with a carrier wave and transmitted from an antenna through an amplifier circuit.

Next, the configuration of the receiving system 20 which receives and reproduces the transmission frame from the transmitting system 10 will be described. As shown in FIG. 3, the receiving system 20 includes an RF unit 21, a control circuit 23, a vocoder 25, and a D / A.
The converter 27 and the speaker 29 are provided.

The RF unit 21 receives a radio signal of a predetermined frequency from the transmission system 10 via the antenna by the tuning circuit, demodulates it, and outputs a baseband signal.

The control circuit 23 includes a processor and a DSP (Di
The frame synchronization signal and the synchronization packet in the baseband signal output from the RF unit 21 are detected, the frame synchronization is established, the wireless header is taken in, and the voice packet of the subsequent voice packet is acquired. Of these, the sync packet is replaced with a comfort noise silent packet, a control packet is added to each voice packet, and the voice packet is sequentially transmitted to the vocoder 25.

More specifically, the control circuit 23 functionally includes a synchronization detection circuit 231, a control unit 233, and a pseudo silence packet generation unit 235.

The synchronization detection circuit 231 is used in the RF unit 21.
The frame synchronization signal in the wireless header and the synchronization packet in the voice packet in the baseband signal provided by the are searched for frame synchronization, and the synchronization signal is output to the control unit. The pseudo-silent packet generation unit 235 uses the vocoder 2
Information for controlling the volume and spectrum of comfort noise generated by the comfort noise generating unit 255 described later in 5 (including a 6-bit header indicating a packet of comfort noise, noise volume and spectrum information) A 48-bit silent packet containing 42-bit data) is generated.

The control unit 233 extracts the voice packet following the radio header according to the synchronization signal from the synchronization detection circuit 231, and when the voice packet is the synchronization packet,
Replace sync packets with silence packets. Control unit 233
If a voice packet is a voice packet, a 14-bit control packet with a silence flag turned off
Add 4-bit dummy data to the voice packet,
Supply to the vocoder 25. If the voice packet is a synchronization packet, the control unit 233 turns the silence flag ON.
The 2-bit control packet and the 144-bit dummy data are added to the replaced silent packet, and the voice packet (48 bits) is serially supplied to the vocoder 25.

The vocoder 25 is composed of, for example, an AMDE series vocoder IC sold by DVSI, and separates the data supplied from the control unit 233 into a control packet, a voice packet, and dummy data. The internal control is performed based on the content of the control packet, 20 ms of voice PCM data is generated from the voice packet, and 20 minutes from the voice packet.
Generate comfort noise PCM data for ms,
Supply to D / A converter.

More specifically, the vocoder 25
Functionally, as shown in FIG. 3, an analysis unit 251, a decoder 253, a comfort noise generation unit 255,
And a multiplexer 257.

The analysis unit 251 separates the data supplied from the control unit 233 into a control packet, a voice packet, and dummy data, performs internal control based on the contents of the control packet, and silences the control packet. Based on whether the flag is on or off, it is determined whether the attached voice packet is a voice packet or a silent packet, and the voice packet is decoded by the decoder 25.
3, the silent packet is converted into the comfort noise generation unit 255.
Output to.

The decoder 253 generates PCM voice data for 20 ms from the voice packet provided from the analysis unit 251.

The comfort noise generator 255 outputs a PCM signal of comfort noise for 20 ms with a volume and spectrum according to the content of the silent packet provided from the analyzer 251.

The multiplexer 257 receives the audio PCM data from the decoder 253 and the noise PC from the comfort noise generator 255 according to the control signal from the analyzer.
Switch between M data and output.

The D / A converter 27 converts the PCM data provided from the vocoder 25 into an analog audio signal and outputs the analog audio signal, and the speaker 29 outputs the sound.

Next, the operation of the voice communication system having the above configuration will be described.

First, the operation of the transmission system 10 will be described with reference to the flowcharts of FIGS. The microphone 11 picks up voice and outputs the analog voice signal S11 to A /
It is supplied to the D converter 13 (step S11). A /
The D converter 13 samples the analog audio signal from the microphone 11 at 16 bits and 8 kHz, converts it into 16-bit PCM data D11, and supplies it to the vocoder 15 by a serial interface for each sample (step S13).

The control unit 155 of the vocoder 15 analyzes the supplied PCM data, and detects a silent state due to breathing or breaks in words. The control unit 155 outputs an operation enable signal to the encoder 151 at the timing at which the voiced state (not the silent state) is detected, and the encoder 151 outputs 160 samples (16 bits × 16 bits × 16 bits) of PCM data.
(160 = 2560 bits) An encoding process is performed for each D13 to generate a 48-bit voice packet D15 (step S15). Encoding time interval is 1 /
It becomes 8 kHz × 160 = 20 ms. On the other hand, the control unit 15
5 detects the silent state, the silent packet generator 15
3 and outputs the operation enable signal to the silence packet generator 153. The silence packet generator 153 includes a 48-bit header including a 6-bit header indicating that the packet is comfort noise and 42-bit data including noise volume and spectrum information. A silent packet (D17) is generated (step S17).

The control unit 155 controls the 192-bit control packet D19 and the 144-bit dummy data D.
21 and 21 are generated. The control packet D19 includes a silence flag indicating whether or not there is a silence state. Control unit 1
55 detects that it is in a silent state, and turns on this silent flag.

Under the control of the control circuit 155, the synthesizing unit 157 combines the control packet (silence flag off) D19, the voice packet D15 from the encoder 151, and the dummy data D21 in the voiced state to combine the 384-bit data D23. Is generated and output to the control circuit 17 (step S19). Also, the synthesizing unit 157, in the silent state, sends a control packet (silent flag ON) D19.
The silent packet D17 and the dummy data D21 are combined to generate the 384-bit data D23, and the control circuit 17
(Step S19).

The separating unit 171 of the control circuit 17 divides the 384-bit data D23 from the vocoder 15 into control data D19, voice packets (voice packets D15 or silence packets D17), and dummy data (step S21). The interpretation unit 173 determines the silence flag of the separated control packet D19 and determines whether the provided voice packet D15 is a voice packet or a silence packet D17. The replacing unit 177 outputs the voiced packet D15 as it is, and outputs the silent packet D17 by replacing it with the synchronization packet D25 provided from the synchronization packet generation unit 175 (step S23).

The wireless header adding section 179 adds a wireless header at the beginning of transmission, and thereafter, a voice packet (voice packet D15 or sync packet D2) provided by the replacing section.
5) is repeated to generate the transmission frame D29 and RF
The data is output to the unit 19 (step S25). The wireless header D27 contains a 64-bit bit synchronization signal and 1
It includes a 5-bit frame synchronization signal and 272-bit header information.

The RF unit 19 sends this transmission frame D
The IQ signal is generated from 29, this is orthogonally transformed, and GM
Generate an SK signal. Then, this signal is mixed with a carrier wave and transmitted from an antenna through an amplifier circuit (step S
27).

In this way, when there is no sound, the wireless frame in which the synchronization packet is inserted is transmitted from the transmission system 10.

Next, the receiving operation of the receiving system 20 will be described with reference to the flow charts of FIGS. The RF unit 21 of the reception system 20 receives the radio signal from the transmission system 10, demodulates it, and reproduces the baseband signal D31 (= transmission frame D29) (step S31).

The synchronization detection circuit 231 of the control circuit 23 is R
Baseband signal D31 provided from F unit 21
The frame synchronization signal in the wireless header D33 in the inside and the synchronization packet in the voice packet are searched for frame synchronization, and the synchronization signal is output to the control unit 233 (step S3).
3). The synchronization detection circuit 231 can reestablish the synchronization by the synchronization packet D25 even if the synchronization is lost for some reason after the synchronization is established by the frame synchronization signal. Further, the synchronization detection circuit 231 can synchronize with the synchronization packet D25 even when the reception is started in the middle of the frame.
It is possible to establish synchronization by.

The control unit 233 sequentially extracts the voice packets following the wireless header D33 according to the synchronization signal (step S35). The control unit 233 determines whether the extracted packet is the voice packet D35 or the synchronization packet D37.
If it is the synchronization packet D37, the synchronization packet D37 is transmitted to the pseudo silent packet generation unit 23.
The silent packet D39 from 5 is replaced (step S3).
7). The control unit 233 determines that the voice packet is the voice packet D
In the case of No. 35, data D4 obtained by adding a 192-bit control packet D41 with the silence flag off and 144-bit dummy data D43 to the voice packet D35.
5 is supplied to the vocoder 25. In addition, the control unit 233
When the extracted voice packet is the synchronization packet D37, the data D45 added to the silence packet D39 in which the 192 bit control packet D41 with the silence flag turned on and the 144 bit dummy data D43 are replaced.
Is supplied to the vocoder 25 (step S39).

The analysis unit 251 of the vocoder 25 has the control unit 2
The data D45 supplied from 33 is separated into a control packet D41, a voice packet D35 or D39, and dummy data D43, and the control packet D41
Internal settings are made based on the contents of (step S4
1). Furthermore, the analysis unit 251 determines whether the voice packet is the voice packet D35 or the voice packet D3 based on whether the voice flag in the control packet D41 is on or off.
If it is a voice packet, the decoder 253 performs a decoding process to obtain 16 bits, 1
The PCM data D47 for 60 samples is generated (step S43). On the other hand, the voice packet is the silent packet D3.
If it is 9, the comfort noise generation circuit 255
According to the content and volume of the silent packet D39, 16 bits, 160 samples (20 ms)
Min) comfort noise PCM data D47 is generated.

Multiplexer 257 is the PCM of these
Data is switched as appropriate, one PC for every 1/8 kHz
The M data is output to the D / A converter 27 (step S45).

The D / A converter 27 samples the PCM data provided from the vocoder 25 at 16 bits at 8 kHz, converts it into an analog audio signal and outputs it (step S47), and outputs it from the speaker 29 (step S49). ).

As described above, according to the voice communication system of this embodiment, as compared with the conventional system,
It is possible to reliably perform frame synchronization processing even during communication without lowering transmission efficiency. Further, the existing vocoder IC can be used, and the design is easy.

(Second Embodiment) In the first embodiment, the transmitting side replaces a silent packet with a sync packet, and the receiving side replaces this sync packet with a silent packet for generating comfort noise. Is replacing. The method is not limited to this method. For example, the transmitting side may transmit a silent packet of a preset (fixed) 48-bit data string so that the receiving side does not need to replace the synchronization packet with the silent packet. You may The specific data string controls the comfort noise generation unit 255 of the reception system 20 to generate the comfort noise with the specified parameters.

In this case, for example, as shown in FIG. 6A, the synchronization packet generation unit 175 of the control unit 17 of the transmission system 10 of FIG. 2 stores the specific pattern packet storage unit 175a for storing the silent packet of the specific pattern. Is replaced by Further, the replacing unit 177 replaces the silent packet generated by the silent packet generating unit 153 of the vocoder 15 with the specific pattern silent packet stored in the specific pattern packet storage unit 175a. On the other hand, the receiving system 20
Then, as shown in FIG. 6B, it is not necessary to dispose the pseudo silence packet generation unit in the control circuit 23. The synchronization detection circuit 231 searches the frame synchronization signal in the header part and the specific pattern data in the audio data to establish frame synchronization. The comfort noise generation unit 255 also generates a noise PCM signal with a volume and spectrum according to the content of the silent packet of the specific pattern. With such a configuration as well, the system can be configured using an existing vocoder IC, and similar effects to those of the first embodiment can be obtained. Further, in this case, the receiving system 20 does not need to dispose the pseudo silence packet generation unit 235 or replace the synchronization packet with the pseudo silence packet in the control unit 233 as illustrated in FIG. 6B. Therefore, the system configuration can be simplified.

(Third Embodiment) Further, the basic configuration of the transmission system 10 shown in FIG. 2 is changed as shown in FIG. 7A, and the silence packet generator 153 generates silence packets of a specific pattern. Then, this is combined by the combining unit 157,
It is also possible that the vocoder 15 outputs a voiced packet or a silent packet of a specific pattern, and a wireless header adding section 179 adds a wireless header to the packet and transmits the packet. In this case, the system configuration can be further simplified.

The present invention is not limited to the first to third embodiments described above, and various modifications and applications are possible. For example, the circuit configurations shown in FIGS. 1 to 3, 6 and 7 and the operation flows shown in FIGS. 4 and 5 are merely examples, and any configuration can be adopted as long as the same function can be realized. Is.

[0077]

As described above, according to the present invention, frame synchronization can be easily achieved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a voice communication system according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a transmission system in FIG.

FIG. 3 is a configuration diagram of a receiving system in FIG.

FIG. 4 is a flowchart and a data transition diagram for explaining the operation of the transmission system.

FIG. 5 is a flow chart and a data transition diagram for explaining the operation of the receiving system.

FIG. 6 is a configuration diagram of a voice communication system according to an application example of the second embodiment of the present invention, in which (a) shows a transmission system and (b) shows a reception system.

FIG. 7 is a configuration diagram of a voice communication system according to an application example of a third embodiment of the present invention, in which (a) shows a transmission system and (b) shows a reception system.

[Explanation of symbols]

10 Transmission system 20 Receiving system

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5K030 GA12 HA08 HB01 HB15 JL01                       KA19 KA21 LA06 LA15                 5K067 AA11 AA23 AA33 BB01 CC04                       CC08 DD25 EE71 GG01 GG03                       GG11 HH21 HH22

Claims (13)

[Claims] 1. A transmitting side divides an input voice signal at regular intervals to detect whether the voice signal in each section is voiced or silent, and when it is voiced, the section is detected. And analyzing the parameters that characterize the voice waveform in S., and transmitting a voiced packet containing the parameter as a voice packet, and when there is no voice, transmitting a voiceless packet including the parameter of the comfort noise generated by the receiving side as a voice packet. Then, on the receiving side, when the received voice packet is a voice packet, the voice signal is reproduced according to the parameter included in the voice packet, and when the voice packet is a silent packet, the comfort noise is generated according to the parameter included therein. In a voice communication system, the voice packet to be transmitted is silent on the sending side. When the packet is a packet, the silent packet is replaced with a synchronization packet composed of a frame synchronization signal and transmitted, and the reception side continuously monitors the reception signal, and when the synchronization packet is detected, the frame synchronization is performed. A voice communication system characterized by performing processing and replacing a detected synchronization packet with a pseudo silence packet that is separately generated. 2. The transmitting side divides an input voice signal at regular intervals to detect whether the voice signal in each section is voiced or silent, and when the voice signal is voiced, the section is detected. And analyzing the parameters that characterize the voice waveform in S., and transmitting a voiced packet including the parameter as a voice packet, and when there is no voice, a voiceless packet including the parameter of the confauto noise generated on the receiving side as a voice packet. At the receiving side, when the received voice packet is a voice packet, the voice signal is reproduced according to the parameter included in the voice packet, and when the voice packet is a silent packet, the comfort noise is generated according to the parameter included in the voice signal. Voice communication system, the sender does not have any voice packets to send. When the packet is a sound packet, the silent packet is replaced with a preset specific silent packet and transmitted, and the reception signal is continuously monitored on the receiving side, and when the specific silent packet is detected, An audio communication system characterized by performing frame synchronization processing. 3. The transmitting side detects whether the input voice signal is voiced or silent, and when it is voiced, a voiced packet is transmitted, and when it is not voiced, a predetermined packet is transmitted. On the receiving side, when the received voice packet is a voice packet, the voice signal is reproduced, and when the voice packet is a predetermined packet, the voice signal is synchronized and the comfort noise is output based on the predetermined packet. . 4. The transmitting side transmits a synchronization packet as the predetermined packet when the input voice signal is silent, the receiving side monitors the received signal, and when the synchronization packet is detected, a frame is transmitted. While performing the synchronization process,
The voice communication system according to claim 3, wherein the detected synchronization packet is replaced with a packet including a comfort noise parameter, and comfort noise is generated according to the replaced packet. 5. The transmitting side transmits a packet containing a fixed parameter when the input voice signal is silent, the receiving side monitors the received signal, and when the packet containing the fixed parameter is detected, a frame is generated. The voice communication system according to claim 3, wherein the comfort noise is generated according to the parameter stored in the packet including the fixed parameter that is detected while performing the synchronization process. 6. An input means for inputting a voice signal and dividing the voice signal at regular intervals, and detecting whether the voice signal in each section is voiced or silent, and when the voice signal is voiced, reproduces the voice signal. VOCODER that outputs a voiced packet including information for performing output, and when there is no voice, determines a vocoder that outputs a silent packet that includes the parameters of the confocal noise generated on the receiving side, and the type of the packet output by the vocoder. A transmission system including: a replacement unit that replaces a silent packet with a predetermined synchronization packet; and a control unit that adds a wireless header to the voice packet and the synchronization packet replaced by the replacement unit to generate a transmission frame. . 7. Input means for inputting a voice signal and dividing the voice signal at regular intervals, and detecting whether the voice signal in each section is voiced or silent, and when it is voiced, reproduces the voice signal. VOCODER that outputs a voiced packet containing information for outputting a voiceless packet that includes a parameter of the confot noise of the receiving side when there is no voice, and a voiceless packet output from the vocoder to detect synchronization of the receiving side. Control means for replacing a packet with a specific pattern that enables frame synchronization by a circuit, adding a wireless header to the replaced specific pattern packet and the voice packet from the vocoder, and generating a transmission frame; A transmission system comprising means for wirelessly transmitting a transmission frame. 8. An input means for inputting a voice signal and dividing the voice signal at regular time intervals, and detecting whether the voice signal in each section is voiced or silent. When the voice signal is voiced, the voice signal is reproduced. Output a voiced packet containing information for performing the output, and outputs a voiceless packet of a specific pattern that includes the parameter of the reception-side confocal noise and enables frame synchronization by the synchronization detection circuit on the reception side when there is no sound. A transmission system, comprising: a means for adding a wireless header to the voiced packet and the silent packet to generate a transmission frame, and wirelessly transmitting the generated transmission frame. 9. Receiving means for receiving and demodulating a radio frame including a radio header containing a frame synchronization signal and a plurality of voice packets following the radio header; and a radio frame in the radio frame demodulated by the receiving means. Sync detection means for detecting frame synchronization based on a frame sync signal and a specific packet in the voice packet, and reproducing voice based on a packet other than the specific packet in the voice packet, and the specific packet Generating means for generating comfort noise based on the above. 10. A specific packet in the voice packet is composed of a synchronization packet, and the synchronization detection means comprises means for replacing the synchronization packet with a silent packet including a parameter for generating comfort noise, the generation 10. The reception according to claim 9, wherein the means comprises a vocoder that reproduces voice based on a packet other than the specific packet in the voice packet and generates comfort noise based on the silent packet. system. 11. A wireless header including a frame synchronization signal,
Receiving means for receiving and demodulating a radio frame including a plurality of voice packets following the radio header, a frame synchronization signal in the radio frame demodulated by the receiving means, and a packet of a specific pattern in the voice packet. Sync detecting means for detecting frame synchronization on the basis of the packet, voice is reproduced based on a packet other than the specific packet in the audio packet, and comfort noise is generated by using information included in the packet of the specific pattern as a parameter. And a vocoder that generates the noise signal of 1. 12. A voice communication method for wirelessly communicating voice from a transmitting side to a receiving side, comprising:
A packet signal including voice data is transmitted, in a silent state, a synchronization packet is transmitted, and at the receiving side, frame synchronization is performed using a synchronization packet, and for a packet signal including voice data, voice is reproduced. A voice communication method comprising: replacing a synchronization packet with a silent packet for generating comfort noise, and generating and outputting comfort noise using the replaced silent packet. 13. An input voice signal is detected whether it is voiced or silent, and when it is voiced, a voiced packet for reproducing voice is transmitted. A fixed packet including a fixed parameter of auto noise is transmitted, and when the received voice packet is a voice packet, the voice signal is reproduced on the receiving side, and when the received voice packet is a fixed packet, synchronization with the fixed packet is performed. A voice communication method, characterized in that comfort noise is generated and output using a fixed parameter in the fixed packet.