JP2576782B2 - Voice communication control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used for controlling voice communication. The present invention relates to a speech signal that transmits a speech signal in a burst only when there is sound, and that artificially inserts noise into a silent section between speech and speech using a control signal that distinguishes speech from speech. It relates to a communication control method.

[0002]

2. Description of the Related Art In a communication system having a limited transmission capacity, such as satellite communication, communication is performed using a system in which a signal of only a sound portion where voice is present is transmitted in a burst manner, and a silent portion is not transmitted / received. By doing so, the transmission path is used effectively to save power. In such a device, a silent part sandwiched between a sound part and the next sound part becomes completely silent, and therefore, the user feels strangeness.

For this reason, by inserting a certain level of pseudo noise into a silent portion in a circuit on the receiving device side,
A method for reducing this discomfort is used. At the end of the voiced part, noise determined to be silent on the transmitting side is added only to the time constant part called the hangover time, so the noise inserted into the silent part using the transmitting side noise of this part Is controlled (Japanese Utility Model Laid-Open No. 60-108048).

FIG. 2 shows an example of the configuration.
When the control signal has sound, the received signal is output as a reproduction signal through the selection circuit 204. The level of the received signal is measured by the level measuring circuit 201 and output. The holding circuit 202 holds the output of the level measurement circuit 201 at the timing when the control signal indicating the distinction between sound and silence changes from sound to silence. The noise generation circuit 203 outputs a level equal to the held level and inputs the same to the selection circuit 204. The output of the selection circuit 204 switches from the received signal to the output of the noise generation circuit 203 at the timing when the control signal changes from sound to silence, and the output noise continues to be output while the control signal is silent. FIG. 3A shows the waveform of the received signal, and FIG. 3B shows the operation of the control signal.

[0005] Japanese Patent Application Laid-Open No.
No. 182644 discloses a noise level signal which discriminates whether a reception output channel is allocated to a relay channel and gradually attenuates the noise signal level with the passage of time. The control signal is used to generate a pseudo noise signal. Further, as disclosed in JP-A-2-276329,
Detects background noise included in the hangover time from data received by the receiving side without sending information about noise during a call from the transmitting side to the receiving side, and background noise substantially equal to the noise included in the transmitting side Is given to the receiving side.

[0006]

When the configuration shown in FIG. 2 is used, the level of the inserted noise on the receiving side is adjusted to the level of the noise on the transmitting side included at the end of the voiced part. Background noise artificially inserted changes dynamically every time it is inserted because it is influenced every time. The noise included on the transmitting side is below the threshold value for sound and silence, but sometimes fluctuates every time because it is very small or at almost the same level as the threshold value. For this reason, there is a problem that the artificially inserted background noise similarly fluctuates greatly every time, and when the noise is relatively large, the user may feel uncomfortable. In particular, when the background noise rises sharply, the sense of discomfort is large.

The present invention solves such a problem. It is possible to average the insertion noise for each section from the beginning to the end of communication, and to prevent the insertion noise from being too low when the noise level is low. It is an object of the present invention to provide a method capable of reducing discomfort due to noise.

[0008]

SUMMARY OF THE INVENTION The present invention uses a control signal for distinguishing between a sound section and a silent section of an incoming voice signal and inserts a low-level background noise into the silent section of the voice signal. Generating means, and a level measuring circuit for measuring the level of the audio signal, wherein the output noise level of the noise generating means corresponds to the audio signal level of the immediately preceding sound section according to the measurement result of the level measuring circuit. In the voice communication control device to be changed, a holding circuit that holds the measurement result of the measurement circuit until the next silent section, a measurement result of the last part of the sound section measured by the level measurement circuit, and the holding circuit holds And a level setting circuit for comparing the measurement result of the immediately preceding sound section with the level of the background noise so as not to change abruptly.

The level setting circuit adjusts the level of the background noise so as not to increase rapidly, and the level setting circuit sends the measurement result of the last part of the sound section immediately before the level measurement circuit to the holding circuit. When the measurement result is larger than the measurement result for the immediately preceding voiced section, a value corresponding to the average value of the two measurement results is set as the setting output, and the measurement result of the last part of the voiced section immediately before the level measurement circuit is obtained. When the measurement result is smaller than the measurement result of the immediately preceding voiced section held in the holding circuit, it is desirable to set the value corresponding to the measurement result of the last part of the immediately preceding voiced section as the setting output.

[0010]

The level measuring circuit measures the signal level received immediately before. The holding circuit holds the measured level at the timing when the control signal indicating the distinction between silence / speech changes from speech to silence, and the level setting circuit immediately before the output value from the level measurement circuit at the same timing as the previous value. The level held at the control signal change point is read, and the current level from the level measurement circuit is compared with the previous level held in the holding circuit. If the current level is higher than the previous level, the average value of the previous level and the current level is output. If the current level is lower than the previous level, the current level is output as it is. The noise generating circuit receives the output and outputs substantially the same level of noise. The selection circuit receives the output and outputs the received signal when the control signal is sound, and outputs the noise from the noise circuit when there is no sound.

[0011] Thus, the insertion noise can be averaged for each section from the start to the end of the communication, and the discomfort caused by the insertion noise can be reduced.

[0012]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention.

The embodiment of the present invention uses a control signal for distinguishing between a voiced section and a silent section of an incoming voice signal, and inserts a low-level background noise into a voiceless section of the voice signal, and A selection circuit 5; and a level measurement circuit 1 for measuring the level of the audio signal. The output noise level of the noise generation circuit 4 is changed to the audio signal level of the immediately preceding voiced section according to the measurement result of the level measurement circuit 1. A holding circuit 2 for holding the measurement result of the level measurement circuit 1 to the next silent section in the receiving apparatus 100 correspondingly changed, a measurement result of the last part of the sound section measured by the level measurement circuit 1 and the holding thereof. A level setting circuit for comparing the measurement result of the previous sound section held by the circuit with the level of the background noise so as not to change abruptly;

The level setting circuit 3 adjusts the level of the background noise so as not to increase sharply, and the measurement result of the last part of the sound section immediately before the level measurement circuit 1 is stored in the holding circuit 2. If the measurement result is larger than that of the previous voiced section, a value corresponding to the average value of both the measurement results is set as a set output, and the measurement result of the last part of the voiced section immediately before the level measurement circuit 1 is held in the holding circuit 2 When the measured result is smaller than that of the immediately preceding sound section, a value corresponding to the measurement result of the last part of the immediately preceding sound section is set as the setting output.

Next, the operation of the embodiment of the present invention configured as described above will be described.

The received signal is input to the selection circuit 5 and the level measurement circuit 1. The level measurement circuit 1 constantly measures the immediately preceding signal level, and inputs the measured value to the holding circuit 2 and the level setting circuit 3. The holding circuit 2 holds the level measured by the level measuring circuit 1 at the timing when the control signal indicating the distinction between the sound and the sound changes from sound to silence. The level setting circuit 3 reads the output value of the level measurement circuit 1 immediately before the control signal changes from sound to silence and the level held at the previous control signal change point, and reads the level measurement circuit 1 Output level (this level)
And the output level of the holding circuit 2 (previous level), and if the current level is higher than the previous level (> or ≧), an average value of the previous level and the current level is output, and If the level is lower than the previous level (<or ≦), the current level is output as it is.

The output of the level setting circuit 3 is a noise generation circuit 4
, And the noise generation circuit 4 inputs the noise having a level substantially equal to the input level to the selection circuit 5. Selection circuit 5
Outputs a received signal when the control signal has sound, and outputs noise output from the noise generation circuit 4 when there is no sound. The noise level to be inserted is determined and determined using the noise on the transmitting side of the past burst received signal and the noise on the transmitting side of the latest burst received signal.

[0018]

As described above, according to the present invention, the insertion noise level is determined by referring to the past value of the transmission-side noise attached to the end of the sound portion, and thereby, from the beginning to the end of the communication. It is possible to average the insertion noise for each section, and to prevent the insertion noise from being too low when the noise level is low, thereby reducing the sense of discomfort caused by the insertion noise.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional example.

3A is a diagram illustrating a received signal waveform, and FIG. 3B is a diagram illustrating an operation of a control signal.

[Explanation of symbols]

 1, 201 level measuring circuit 2, 202 holding circuit 3 level setting circuit 4, 203 noise generating circuit 5, 204 selecting circuit 100, 200 receiving device 110 transmitting device

Claims (3)

(57) [Claims] 1. A noise generating means for inserting a low-level background noise into a silent section of an incoming audio signal using a control signal for distinguishing between a sound section and a silent section of the incoming audio signal,
A level measuring circuit for measuring the level of the audio signal, wherein the output noise level of the noise generating means is changed in accordance with the level of the audio signal in the immediately preceding sound section in accordance with the measurement result of the level measuring circuit. In the communication control device, a holding circuit for holding a measurement result of the measurement circuit until a next silent section, a measurement result of a last portion of a sound section measured by the level measurement circuit, and a previous one held by the holding circuit. And a level setting circuit for comparing the result of the measurement with respect to the sounded section with the level setting circuit so as to prevent the level of the background noise from changing abruptly. 2. The voice communication control device according to claim 1, wherein the level setting circuit adjusts the level of the background noise so as not to increase sharply. 3. The level setting circuit according to claim 1, wherein the measurement result of the last portion of the sound section immediately before the level measurement circuit is larger than the measurement result of the immediately preceding sound section held in the holding circuit. A value corresponding to the average value of the measurement results is set as a set output, and the measurement result of the last part of the sound section immediately before the level measurement circuit is obtained from the measurement result of the immediately preceding sound section held in the holding circuit. 3. The voice communication control device according to claim 2, wherein when the value is smaller, a value corresponding to the measurement result of the last portion of the immediately preceding sound section is set and output.