JP2962343B2 - Conference call system with audio signal level control function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conference call system with a voice signal level control function, and more particularly to a voice signal level control device for a conference call by a number of conferees via a communication switching network.

[0002]

2. Description of the Related Art A conventional conference call system with an audio signal level control function is disclosed, for example, in Japanese Patent Application Laid-Open Nos. H03-032266, 59-15367, and 03-10886.
As disclosed in Japanese Patent Publication No. 3 (1993) -3, a conference trunk apparatus having an N-1 adder circuit is used for the purpose of providing a clear voice by optimizing the voice level of each conference participant.

The above-mentioned Japanese Patent Application Laid-Open No. 03-322266 will be described with reference to FIG. As shown in FIG. 3, a time-division switch 21 which can be replaced for each time slot, a central control processing unit 23, a dropper 22 for dropping control information from the central control processing unit 23, and a serial / parallel conversion circuit for performing parallel conversion of audio signals. 25, a parallel-to-serial conversion circuit 26 for performing the inverse conversion thereof, a silence signal detection circuit 28 for determining the number of conference participants, a voice attenuation circuit 27 for controlling the voice level of the input signal for each conference participant, a voice signal control. It comprises a conference trunk control circuit 24 for creating information 33 and controlling the audio signal attenuating circuit 27, and a conference trunk circuit 29 for performing N-1 addition. The operation will be described below.

First, an audio signal time-division multiplexed by the time division switch 21 and a conference trunk control signal from the central control processor 23 are input to the conference trunk circuit 29 through the input highway 31. Only the conference trunk control information is dropped by the dropper 22 and received by the conference trunk control circuit 24. The audio signal is converted into a parallel signal by the serial / parallel conversion circuit 25, and a silent signal detection circuit 28 detects a silent signal to calculate the number of conference participants. Voice signal control information is created based on the conference trunk control information and the number of conference participants, and control is performed for each conference participant.

[0005]

However, in the conference call system with the audio signal level control function disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 03-032266, the audio level is controlled for each conference participant. The audio level is set by the silence detection circuit 28 for detecting the number of conference participants and the control signal from the central control processing unit 23, but the control method for creating this control signal is large-scale and complicated. There was a problem.

As described above, the conventional conference call system with the audio signal level control function is roughly divided into two systems.
The first method is based on a conference call system with an audio signal level control function disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 03-032266. A method of discriminating the number of participants, attenuating the audio signal level of each conference participant according to the number of participants, and thereby attenuating the audio signal level of the entire conference participant. In this method, the audio signal level to which −1 has been added is detected, and if the audio signal level of the entire conferee overflows, the attenuation of the audio signal level of the entire conferee is controlled.

In this case, in the first method, since the level of the audio signal is attenuated individually for each of the conferees, if the cause of the overflow is actually all the conferees, individual judgment is not performed, but the entirety is determined. It is better to control the level of attenuation. On the other hand, in the second method, since the audio signal level is attenuated for the entire audio signal to which N-1 has been added, if the cause of the overflow is actually an individual conference person, the individual audio signal is rather reduced. It is better to control the damping only for this. Furthermore, in this case, if the attenuation is not performed individually and the entire attenuator is attenuated, the individual attendees are uniformly attenuated, so that there is a problem that the voice level of each conferee after control becomes unclear.

An object of the present invention is to provide a conference call system with a voice signal level control function for solving the above problems.

[0009]

According to the present invention, an audio signal level adjusting circuit capable of controlling audio signals of a large number of conference participants in a conference call system using an N-1 addition system without adding its own voice. And an audio signal control unit for creating and transmitting control information for controlling the audio signal level adjustment circuit, wherein the audio signal control unit receives the audio signal added by N−1, and Detects whether the overflow has occurred and if an overflow is detected,
Next, the audio level of each input audio signal is detected, and
Speaker's voice signal is clearer than other specific conferee's voice signal
If it is too high, the audio signal of that particular conference
And the audio signal of a specific conference
When it is clearly not excessive compared to the voice signal of the legislator
Controls to attenuate the audio signal level of the entire conference
Thus , a conference call system with a voice signal level control function can be obtained.

Further, according to the present invention, the audio signal control section includes an overflow detection circuit, an audio level detection circuit, and an audio signal control circuit, and the overflow detection circuit is configured to add an audio signal of each conferee. An audio signal level and presence / absence of overflow; the audio level detection circuit detects an audio signal level of each of the conferees; and the audio signal control circuit detects the overflow and outputs audio of each input audio signal. Detect level
As a result, the audio signal of a specific conference
If it is clearly larger than the voice signal, the specific meeting
Control to attenuate only the voice signal of the user
A signal is sent, and the audio signal of a specific conference
If the audio signal is clearly not excessive compared to the
The second control is used to attenuate the voice signal level of the whole parliament.
A control signal , wherein the audio signal level adjustment circuit receives the first and second control signals and controls the level of the audio signal in predetermined steps according to the control signals. A conference call system with a signal level control function is obtained.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a conference call system with a voice signal level control function of the present invention. The conference call system with the audio signal level control function according to the present invention includes a time-division switch 1 for switching each time slot, a serial / parallel conversion circuit 4 for performing parallel conversion, and a parallel / serial conversion circuit 5 for performing reverse conversion. A decompression circuit 2 for converting a quantized PCM signal into a linear PCM signal, and a compression circuit 3 for performing the inverse conversion.
An audio signal level adjustment circuit 6 for controlling the input audio signal for each conference participant in fine steps;
It comprises a conference trunk circuit 8 that performs N-1 addition without adding its own voice, and an audio signal control unit 7 that generates audio signal control information for controlling the audio signal level adjustment circuit 6.

The configuration of the audio signal control unit 7 is as shown in the block diagram of FIG. 2. The overflow detection circuit 13 detects an overflow from the addition result of the conference trunk circuit 8, and the conferee from the serial / parallel conversion circuit 4. It comprises an audio level detection circuit 14 for detecting individual audio signals, and an audio signal control circuit 12 for creating a control signal for the audio signal level adjustment circuit 6. Next, the operation of the above embodiment will be described.

The audio signal input from the time division switch 1 through the input highway 9 is added N-1 by the conference trunk circuit 8, and the overflow detection circuit 13 determines whether or not an overflow has occurred due to the addition of the audio signal. Is detected. The voice level detection circuit 14 detects whether the voice of a specific conference participant is excessive voice by detecting the level of the input voice.

In the audio signal control circuit 12, from the detection results of the overflow detection circuit 13 and the audio level detection circuit 14, it is determined whether the cause of the overflow is due to the addition of all conference participants or the excessive audio signal of a specific conference participant. To determine if the cause of the overflow is a specific meeting
In the case of participants, the audio signal level control information
Sending the first control signal to the audio signal level adjustment circuit 6;
The overflow is caused by the addition of each conference participant
Contains a second control signal as audio signal level control information.
The signal is sent to the audio signal level adjustment circuit 6, and the audio signal level is adjusted.
The adjusting circuit 6 receives the first and second control signals.
Attenuate the level of the audio signal in finer steps.

The audio signal control circuit 12 generates the second control signal so as to lower the audio level for all conference participants when the overflow is caused by the addition of the conference participants, The signal is sent to the signal level adjusting circuit 6. In this case, since all the conferees cause an overflow, the voice level of all the conferees can be provided to the other party as appropriate voices by uniformly attenuating and controlling the voice levels of all the conferees.

On the other hand, when the cause of the overflow is an overflow by a specific conference participant, the audio signal control circuit 12 generates the first control signal so as to lower the audio level only to the conference participant. And sends it to the audio signal level adjustment circuit 6. In this case, since the specific conference participant is causing the overflow, by controlling only the audio level of the specific conference participant to be attenuated, the call audio of the specific conference participant can be provided to the other party as appropriate audio. . Therefore, extremely clear voice can be provided to the other party.

[0017]

As described above, according to the present invention, when the level of the voice signal added by N-1 by the conference trunk circuit overflows, whether the cause of the overflow is caused by all the conference participants or Since the audio level control information is created based on the result of the discrimination by determining whether or not the conference is performed by a specific conferee, the voice signal level of each conference participant can be controlled in fine steps.
The conference call voice can be provided with appropriate voice.

Further, according to the present invention, the configuration is simpler than that of the conventional method, and the manufacturing cost is excellent.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a conference call system with an audio signal level control function of the present invention.

FIG. 2 is a block diagram illustrating a configuration of an audio signal control unit.

FIG. 3 is a block diagram showing one embodiment of a conventional conference call system with an audio signal level control function.

[Explanation of symbols]

 Reference Signs List 1 time-division switch 2 expansion circuit 3 compression circuit 4 serial-parallel conversion circuit 5 parallel-serial conversion circuit 6 audio signal level adjustment circuit 7 audio signal control unit 8 conference trunk circuit 9 input highway 12 audio signal control circuit 13 overflow detection circuit 14 audio level Detection circuit

Claims (2)

(57) [Claims] 1. An audio signal level adjustment circuit capable of controlling audio signals of a large number of conference participants in a conference call system using an N-1 addition method in which own audio is not added, and controlling the audio signal level adjustment circuit. An audio signal control unit for creating and transmitting control information for performing the operation. The audio signal control unit receives the audio signal added by N-1 and detects whether the audio signal overflows. , Overflow
Is detected, then the audio level of each input audio signal is
Bell is detected and the audio signal of a specific conference
If the sound signal is clearly too loud,
Attenuate only the audio signal of the conference
Audio signal is evident compared to other specific conferee audio signals
If not, adjust the audio signal level of the entire conference
A conference call system with a voice signal level control function, characterized in that control is performed so as to attenuate . 2. The conference call system with an audio signal level control function according to claim 1, wherein the audio signal control unit includes an overflow detection circuit, an audio level detection circuit, and an audio signal control circuit, and the overflow detection circuit includes: Detecting the presence or absence of an overflow and an audio signal level due to the addition of the audio signals of the individual conferees; the audio level detection circuit detects the audio signal level of the individual conferees; and the audio signal control circuit detects the overflow. ,And,
As a result of detecting the audio level of each input audio signal,
The audio signal of the conferees is clearer than the audio signals of other specific conferees.
Is too large, the audio signal of that particular conference
The first control signal to attenuate only the
The audio signal of a specific confereer is compared to the audio signals of other specific conferees.
If it is not clearly excessive, the audio of the entire conference
Sends a second control signal to attenuate signal level
The audio signal level adjustment circuit receives the first and second control signals and controls the level of the audio signal in predetermined steps according to the control signals. Conference call system.