JPH0546146U - VOX control device in digital communication device - Google Patents

Abstract

(57) [Summary] [Purpose] The silence state is judged by detecting the PCM-encoded silence code. [Structure] The output of the PCM encoding unit 2a is detected by a judgment circuit 3 and, for example, when the same signal is generated for a period of 160 frames, it is judged to be in a silent state.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a VOX control device in a digital communication device that stops transmission when there is no audio signal.

[0002]

[Prior Art]

 Generally, when transmitting, a wireless transmitter puts the transmitter in a press talk state and transmits radio waves. This applies not only to simplex type devices but also to duplex type devices. However, there is a difference in that the duplex type device is in the press talk state until the communication with the other party is cut off.

By the way, operating the transmitter consumes more power than operating the receiver, and particularly in the case of a portable device, transmission may be stopped when it is not necessary in order to reduce battery consumption. desirable. For this reason, conventionally, there has been provided a VOX device which detects the voice signal during a period without a transmitted voice signal, that is, a silent period and stops the transmission.

[0004]

[Problems to be solved by the device]

 However, the conventional VOX directly detects the voice signal, which is an analog signal, regardless of whether it is an analog radio device or a digital radio device, and determines the presence or absence of voice. This detection rectifies the voice signal and integrates it. However, if the integrated value exceeds a predetermined value, the transmitter was started up assuming that there was a voice signal, so even if the voice signal is actually supplied even if a voice signal is actually sent when the transmission is interrupted. Since it is judged that there is voice after the sending time, there is a problem that the beginning of the call may be missing and sometimes an unnatural call must be made.

[0005]

[Means for Solving the Problems]

 In order to solve such a problem, the present invention is provided with a judging means for judging that there is no sound when the same PCM coded data continues for a certain time.

[0006]

[Action]

 Since the PCM-coded silent data continues when there is no sound, the silent data is digitally detected, and when the data continues for a predetermined period of time, it is determined to be in a silent state. As a result, when the silent state is interrupted, there is no silence data and the judgment can be made immediately, so that the call is not cut off.

[0007]

【Example】

 FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, the voice transmitted by the microphone 1 is supplied to the voice processing unit 2 and encoded. The voice encoding unit 2 is composed of a PCM encoding unit (PCM codec) 2a and an ADPCM encoding unit 2b.

The PCM encoding unit 2a is adapted to perform encoding corresponding to the instantaneous value of the input signal, and when the input signal is silent (DC), it generates a constant continuous code. For example, in the case of encoding according to the μ-law, when there is no sound, the continuous state is “1 1111111” indicating a change from minus V to 0V or “01111111” indicating a change from plus V to 0V.

Therefore, in the present application, the output of the PCM encoding unit 2a is monitored by the determination circuit 3, and it is determined to be in the silent state when the output is continued for a certain time. That is, one frame of the above-mentioned PCM code composed of 8 bits has 125 μS, and when this continues for a plurality of frames, for example, 160 frames, it is determined that there is no sound.

The PCM-encoded signal is ADPCM-converted by the ADPCM encoder 2 b and supplied to the radio unit 4 in order to perform more efficient encoding. Then, the radio unit 4 is controlled by the output determined by the determination circuit 3 so that the press talk state is turned on or off. That is, when the judgment circuit 3 detects that there is no sound, the radio talk is stopped by turning off the pre-talk state of the radio section 4, and when the judgment circuit 3 judges that the radio section 4 is not silent, the press talk state of the radio section 4 is set. Turn it on.

The judgment circuit 3 judges whether or not the silent state continues for 160 frames each time the frame is updated. When the silent state is changed to the transmitting state, a new frame becomes an audio signal. Since the corresponding PCM code is supplied, the silent state of 160 frames does not continue, and the transmitter 4 immediately enters the press talk state. This delay time is one frame, that is, about 160 μs. However, with such a delay, it is almost impossible to recognize it as a voice break.

Note that the output of the ADPCM encoding unit 2b changes even in the silent state, so that the determination process is complicated and it is not suitable for detecting silence. Further, the present application need only be a digital type mobile wireless device, and can be used in, for example, a cordless telephone, an automobile telephone, or the like. However, there is a system that judges that the radio wave is out of the communication area when the radio wave is cut off for a certain period of time, but in that case, a special signal is transmitted when the press talk is turned off and the radio wave is cut off because of silence. Therefore, appropriate processing such as notifying the master station that it is not to go out of the communication area may be performed.

[0013]

[Effect of the device]

 As described above, according to the present invention, when the PCM coded code continues for a certain period of time, it is determined that there is no sound. Therefore, unlike the conventional VOX, a head cut does not occur at the beginning of a call. However, it is possible to reduce battery consumption by controlling the wireless device by VOX output while making a call without feeling uncomfortable.

[Brief description of drawings]

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

[Explanation of symbols]

 1 Microphone 2 Voice processing unit 2a PMC encoding unit 2b ADPCM unit 3 Judgment circuit 4 Radio unit

Claims (1)

[Scope of utility model registration request] 1. A VOX control device in a digital communication device which detects the absence of a voice signal when transmitting PCM-coded voice data and transmits the voice when the same PCM-coded data continues for a certain time. A VOX control device in a digital communication device, comprising a determination circuit for determining that there is no signal.