JPS63260250A - Voice packet transmission equipment - Google Patents

Abstract

PURPOSE:To effectively process only an input voice data at the sound period into a packet by setting a threshold value to a proper value in response to the fluctuation of an inputted voice data and noise level. CONSTITUTION:The mean power E of a voice data in a digitized voice signal is calculated by a mean power calculation section 2 and the threshold value L of the mean power E is revised sequentially and compared with a threshold value L of a threshold value storage register 6 by a comparator 3. In case of E>L, the data is discriminated to be a data block of the sound period and in case of E<L, it is discriminated to be a data block of no sound period and only in the sound period, the data is processed into a packet by a packet composing section 4 and sent. On the other hand, a power calculation section 7 calculates the mean value of the mean power E of the block discriminated to be the no sound period over a prescribed period at the no sound and gives a value higher than the value by several dB to the register 6 and an inter-block power ratio calculating section 8 sets the threshold value L when the power is changed comparatively rapidly.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a voice packet transmitting device for performing voice communication using a packet switching method.

(Prior Art) Conventionally, there is a voice packet switching system disclosed in Japanese Patent Laid-Open No. 59-6694, in which a telephone is connected to a voice packet switching network, and voice is packetized and transmitted only when there is a voice. In the above method, the average amplitude value of the input audio data when the user is not talking during a call, that is, when there is no sound, is always compared with the amplitude value of the input audio data, and the amplitude value of the input audio data is If the amplitude is less than the silent amplitude value, the input voice data is discarded to prevent unnecessary packets from being transmitted due to noise in the environment in which the telephone is installed.

(Problem to be Solved by the Invention) However, in the above method, in order to obtain the amplitude value during silent periods, it is necessary to know whether the telephone user is talking or not. Whether this is the case can be determined by the amplitude value of the input audio data. Therefore, if the amplitude value during silence is set to a value lower than the appropriate value due to a temporary change in the input signal level in a silent section, the presence of sound will be determined even during silence, regardless of the presence or absence of voice. There was a problem in that the packets were sent without any delay.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems and provide an audio packet transmitting device that effectively packetizes and transmits only input audio data in a sound section.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention composes audio blocks based on input audio data and divides them into audio blocks of voiced sections and audio blocks of silent sections. In a voice packet transmitting device that packetizes and transmits voice blocks in a voiced section, the average power of the voice blocks is compared with a threshold value to discriminate between a voice block in the voiced zone and a voice block in a silent zone. means, first threshold setting means for updating the threshold according to the average power of each audio block continuously determined as the silent section by the discriminating means over a predetermined period; The average power of each audio block when the ratio of the average power of the audio block of the relevant section that is a sounding section and the audio block of the immediately preceding section is less than a predetermined value for each section over a predetermined period. and second threshold setting means for updating the threshold with a value that corresponds to the power or a value that is preset as the upper limit level of the silent section.

(Operation) According to the present invention, the threshold value used by the discriminating means for discriminating is determined by the discriminating means to be a silent section over a predetermined period with respect to the average power of the input audio block. When the threshold value is updated by the first threshold setting means to a threshold corresponding to the average power of the silent section, and the determining means determines the average power of the audio block to be a sound section over a predetermined period, When the ratio of the level change is less than a predetermined value, the second threshold setting means updates the threshold to a threshold corresponding to the level of the sound section.

(Embodiment) FIG. 1 is a block diagram of a circuit of a voice packet transmitting device showing an embodiment of the present invention.

In the figure, reference numeral 1 denotes an input terminal, into which an audio signal digitized by a PCM signal or the like is input.

Reference numeral 2 denotes an average power calculation unit which calculates the square mean of the amplitude values of audio data (audio block) having the same time length (segment) as the audio block to be packetized by the packet assembling unit 4, which will be described later, ie, the average power E.

3 is a comparator as a discriminating means, which compares the average power E with a threshold value described below, and when it is EEL, the corresponding audio block is a block of data in a sound section, and when it is E, it is a block of data in a silent section. It is determined that it is a block of data.

4 is a packet assembling unit which sequentially packetizes the audio blocks determined by the comparator 3 to be data of a sound interval, and
Send to output terminal 5.

Reference numeral 6 denotes a threshold value holding register that updates and holds the threshold value as needed and supplies the threshold value to the comparator 3.

Reference numeral 7 denotes a silent power calculation unit as a first threshold value setting means, which is a telephone (
The threshold value is set when the environmental noise (not shown) changes relatively slowly, and the comparator 3 continues for a predetermined period exceeding 250 ms and determines that it is a silent period. The average value of the average power E of the audio block is calculated, and a value several dB higher than that value is set and applied to the threshold holding register 6. Note that the reason why a period of 250 ms or more was adopted in calculating the average value is that there is usually no silence shorter than 250 ms in a conversation. The threshold holding register 6 updates the threshold according to the set value.

Reference numeral 8 denotes an inter-block power ratio calculation unit as a second threshold setting means, which sets a threshold when the noise in the environment of the telephone changes relatively rapidly. Regarding the average power E of each audio block that is continuously determined to be a sound section over a predetermined period, the average power En of the audio block in the n-th section and the average value En- of the audio block in the immediately preceding section are calculated. 1 (level ratio) for each section En-1, En over a predetermined period.

Calculations are made for En+l..., and it is determined whether each of them is less than or equal to the allowable level ratio Eth for a silent section. In this determination, if the average power E is increasing gradually and is less than the upper limit Em of the level of the silent section, E n/E n-1, E nil/ E n-< E
th-(1) When the level is decreasing and is below the upper limit Em of the silent section level, E n-1/ E n, E n/ E n
Check whether the condition +L-<Eth-(2) is satisfied. This is because the level ratio of sound data does not fall below a predetermined value, so when the level ratio is below a predetermined level, it is treated as a voice block in a silent section.

The inter-block power ratio calculation unit 8 also calculates equation (1) or (
2) If the conditions of formula are satisfied, each of these average powers En-
The average value of 1, En, En+l, . . . is calculated, a value several dB higher than that value is set as the threshold value, and the threshold value in the threshold value register 6 is updated.

The inter-block power ratio calculation unit 8 also simplifies this and uses the above-mentioned upper limit value Em of the level of the silent section as the threshold value instead of the average value as the upper limit level of the silent section. The threshold value of the threshold value register 5 may be updated.

(Effects of the Invention) As explained above, according to the present invention, the threshold value is updated to an appropriate value in accordance with fluctuations in the noise level of input audio data. Voice data is not unnecessarily packetized and transmitted, and voice packets can be transmitted with high transmission efficiency.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a circuit of a voice packet transmitting device showing an embodiment of the present invention. 3... Comparator (discrimination means) 7... Silent power calculation section (first threshold setting means) 8... Inter-block power ratio calculation section (second threshold setting means) Patent Applicant Oki Electric Industry Co., Ltd. Agent Patent Attorney Yoshi 1) Voice education according to the present invention, , To Transmission II Giant Sunobu b-
Figure 1

Claims (1)

[Claims] An audio packet transmitting device that configures audio blocks based on input audio data, divides the audio blocks into audio blocks in active sections and audio blocks in silent sections, packetizes the audio blocks in active sections, and transmits the packets. Discrimination means for comparing the average power of the voice block with a threshold value to discriminate between the voice block in the voiced section and the voice block in the silent section; a first threshold setting means for updating the threshold according to the average power of each audio block defined as a section; The value is set in advance as a value corresponding to the average power of each audio block or the upper limit level of a silent section when the ratio of each average power to the audio block of the section is less than a predetermined value for each section over a predetermined period. A voice packet transmitting device comprising: second threshold setting means for updating the threshold according to a value.