JPH07202794A - Vox control communication equipment - Google Patents

Abstract

PURPOSE:To realize highly efficient VXO control with less malfunction by reducing speech head interruption under a high noise signal. CONSTITUTION:A voice detector calculates a difference between a mean power of a non-voice frame and an input power, that is, a change in the step ST2-1. A threshold level is calculated inversely proportional to the mean power of the non-voice frame in the step ST2-2. When the change is smaller than the threshold level, a current frame is discriminated to be a non-voice frame. When the frame is discriminated to be a non-voice frame, the weighted mean value between the mean power of the current non-voice frame and the power of the current frame is used for a new mean power of the non-voice frame in the step ST2-4. Since the mean power of the non-voice frame being a criterion is updated, proper VOX control corresponding to the level of noise is realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a VOX (Voice).
The present invention relates to a communication device under the control of an Operated Transmitter). In particular, it relates to a digital mobile communication device or the like by this VOX control.

[0002]

2. Description of the Related Art Conventionally, VOX (Voice Opera) has been used as a method for saving power consumption when transmitting data from a wireless device.
Ted Transmitter) is known. The VOX is a technique of detecting an input voice signal and turning on the power of the transmitter only when the voice signal is present, and turning it off when the voice signal is not present.

In particular, in mobile communication devices such as mobile phones, since the power is supplied by a battery, this VOX is widely used as a power saving technique.

In this VOX, if the rising time from the detection of the voice signal to the turning on of the electric power of the transmitter is too long, so-called head disconnection occurs and the voice becomes hard to hear on the receiving side. Therefore, the detection of the presence / absence of a voice signal is a very important problem.

In the conventional determination as to whether the voice is silent or voiced, a fixed threshold level is set for the input voice level, and the voice level is compared by comparing the magnitudes of these values. / Silence was being determined. Therefore, it is difficult to determine a low-level voice signal such as a consonant, and as a result, the speech head is lost and the sound quality deteriorates.

[0006]

As described above, the conventional V
In a communication device based on OX control, so-called head breakage under a high noise level is severe and the voice quality is extremely deteriorated.

The present invention has been made in view of the above problems, and an object of the present invention is to perform VOX control with high efficiency by reducing breaks in speech under high noise and by reducing malfunctions due to noise.

[0008]

In order to solve the above-mentioned problems, the first invention is a threshold value calculating means for calculating a threshold value based on the average power of a silent frame of an input signal. , A threshold value calculating means for calculating the threshold value in inverse proportion to the average power of the silent frame, the average power of the current frame of the input signal, the difference between the average power of the silent frame, When the change amount is small, comparing the change amount and the threshold value with a change amount calculation means that outputs a change amount indicating how much the average power of the current frame is larger than the average power of the silent frame. Is a frame determination unit that determines the current frame as a silent frame; and, if the current frame is determined by the frame determination unit to be a silent frame, Update means for updating the average power of the sound frame to an average value of the average power of the silent frame and the average power of the current frame, and in the frame next to the current frame, updated by the update means. VO, wherein the average power of the generated silent frames is used in the threshold value calculating means.
It is an X control communication device.

In order to solve the above problems, a second aspect of the present invention is the VOX control communication apparatus according to the first aspect of the present invention, wherein the updating means sets the average power of the silent frame to the average power of the silent frame. The VO is updated to a weighted average value with the average power of the current frame.
It is an X control communication device.

[0010]

The threshold value in the first aspect of the present invention is calculated based on the average power of silent frames. Then, the threshold value calculation means calculates the value of the threshold value so as to be inversely proportional to the average power. Then, the average power of the current frame and the average power of the silent frame are compared, and the change amount thereof is calculated by the change amount calculating means. Then, by comparing this amount of change with the threshold value, the frame determination means determines whether the current frame is a silent frame or a voiced frame.

Further, when it is determined that the frame is a silent frame, the average power of the silent frame is updated to a new value. This updating is performed by the updating means by taking an average value of the average power of the silent frame and the average power of the current frame (which is determined to be the silent frame). In this way, since the threshold value, which is the reference for determining whether or not the frame is a silent frame, is updated for each frame, it is possible to deal with a slight power fluctuation of the input signal.

The updating means in the second aspect of the present invention sets the weighted average value of the average power of the silent frame and the average power of the current frame (judged to be the silent frame) as the average power of the new silent frame. Therefore, a more appropriate average power of silent frames can be obtained, and as a result, an appropriate threshold value can be calculated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a digital mobile communication device which is a preferred embodiment of the present invention. As shown in FIG. 1, in this digital mobile communication device, the analog input voice signal is first converted by the PCM encoder 1.
Is converted into a digital signal. The digital signal converted by the PCM encoder 1 is subjected to predetermined encoding in the voice encoder 2.

A feature of this embodiment is that the speech coder 2 calculates the power value of the input speech signal and supplies it to the speech detector 3. Then, the voice detector 3 internally performs a predetermined calculation to determine whether the current frame is a voiced frame or a silent frame, and outputs the determination result. Then, this determination result is supplied to the wireless unit 4, and the wireless unit 4
It is used to control electric power in.

The calculation of the power in the speech encoder 2 is performed by calculating the sum of squares of the converted digital signals.

The feature of this embodiment is that the threshold value, which is a reference for judging whether the frame is a voiced frame or a silent frame, is adaptively updated based on the power value of the input signal. This is to prevent the so-called voice break by making more appropriate voice / non-voice determination. A flow chart of the internal processing of the voice detector 3 is shown in FIG.

In step ST2-1, the difference between the power of the current frame and the average power of a predetermined silent frame is obtained. As a result, in ST2-1, the amount of change representing how much the average power of the current frame is larger than the average power of the silent frame is calculated.

On the other hand, in step ST2-2, the threshold value is calculated based on the average power of the silent frames. In the calculation of the threshold value in step ST2-2, the threshold value is calculated so as to be inversely proportional to the power of the silent frame. That is, in this embodiment, the threshold value is obtained as a linear function of the power of the silent frame, and the slope of this linear function is set to a negative value.

Next, in ST2-3, the above-mentioned ST2
-2, the threshold value obtained in -2 is compared with the change amount obtained in ST2-1. As a result of this comparison, if it is determined that the change amount is smaller than the threshold value, the average power of the silent frames is updated in step ST2-4, and if the change amount is larger than or equal to the threshold value, In step ST2-5, the frame is determined to be a voiced frame.

In step ST2-4, the average power of silent frames is updated. The value of the average power of the silent frame updated here is obtained by the above-mentioned step S.
It is used in the next frame to calculate the change amount at T2-1. The update in step ST2-4 is performed by calculating a weighted average value of the average power of the silent frames up to that point and the average power of the current frame. The average value calculated in this way becomes the average power of the new silent frame. Here, the average power of the silent frame so far and the power of the current frame are given a predetermined weighting. However, for this weighting, an appropriate value should be selected depending on the noise level and the like. Is.

In step ST2-6, the current frame is determined to be a silent frame, and the voice detector 3 outputs this determination signal to the radio section 4. The wireless unit 4 receives this determination signal and reduces the power consumed by the wireless unit 4.

On the other hand, when it is determined that the current frame is the voiced frame, the determination signal indicating that the voiced frame is the voiced frame is supplied from the voice detector 3 to the radio section 4 in step ST2-5, and the radio signal is transmitted. The unit 4 sets the power consumption of the wireless unit 4 to the normal value by this determination signal.

As described above, in the present embodiment, the silent frame detects the average power of the silent frame which is the basis of the calculation of the threshold value which is the criterion for determining whether the frame is the silent frame or the voiced frame. Since it is updated every time, it has an effect that it is possible to cope with a subtle change in power and it is difficult for the head to be cut off even for the head to start with a consonant. Further, there is an effect that a highly efficient communication device with less malfunction due to noise can be obtained.

[0025]

As described above, according to the first aspect of the present invention, the current frame is determined based on the amount of change between the average power of silent frames and the power of the current frame. Then, the threshold value to be compared with this change amount is set to be in inverse proportion to the average power of the silent frame, and the average power of the silent frame is updated every time the silent frame is detected. Therefore, it is possible to realize a communication device in which so-called head breakage is less likely to occur even for a talk head started with a consonant. Further, since the threshold value is changed quantitatively, it is possible to obtain a communication device capable of performing highly efficient VOX control, since it is possible to cope with a slight power fluctuation due to less noise.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of a digital mobile communication device which is a preferred embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the voice detector 3.

[Explanation of symbols]

 1 PCM encoder 2 voice encoder 3 voice detector 4 radio section

Claims (2)

[Claims] 1. Threshold calculation means for calculating a threshold value based on the average power of a silent frame of an input signal, wherein the threshold value is set so as to be inversely proportional to the magnitude of the average power of the silent frame. Threshold calculation means for calculating, the difference between the average power of the current frame of the input signal and the average power of the silent frame is obtained, and how much the average power of the current frame is larger than the average power of the silent frame is calculated. A change amount calculation unit that outputs a change amount that represents the change amount, compares the change amount and the threshold value, and when the change amount is small, a frame determination unit that determines the current frame as a silent frame; If the means determines that the current frame is a silent frame, the average power of the silent frame is calculated as the average power of the silent frame. And an average value of the average power of the current frame, and updating means for updating, and in the frame next to the current frame,
The VOX control communication device, wherein the average power of the silent frames updated by the updating means is used in the threshold value calculating means. 2. The VOX control communication device according to claim 1, wherein the updating unit sets the average power of the silent frame to a weighted average value of the average power of the silent frame and the average power of the current frame, A VOX control communication device characterized by updating.