JPS6337758A - Conference speech bridge device - Google Patents

Abstract

PURPOSE:To suppress interior noises in an arrival signal by providing plural expanders which expand and supply the level variation of input signals to an adding means and plural compressors which compress and send the level variation of the composite signal back to one channel. CONSTITUTION:The levels of the input signals of respective channels are adjusted so that the mean level at the time of transmission is specific. The difference between the mean level of the input signals of channels during transmission and the means level of input signals of channels during nontransmission increases up to the expansion rate of the expanders 1 after being passed through the expanders 1. Consequently, the input signals of the channels during the transmission are emphasized in the sent signal of the adder 4, and interior noises of the channels during the nontransmission are suppressed relatively. The compressors 2 perform amplification while the emphasis of the sent signal is maintained, and the sent signal which is relatively high in level among input signals of other channels is emphasized, so that the output signal wherein interior noises relatively low in level is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a conference call bridge device, particularly a conference call bridge device for adding transmission signals sent from a plurality of channels and transmitting the signals back to each channel. Relating to a bridge device.

[Conventional technology]

The main function of the conference call bridge device is to receive the transmitted signals coming from multiple channels, add the transmitted signals from other channels to each channel, and add the signal obtained by adding the transmitted signals from the own channel.
It is to send it back. Traditional conference call bridge equipment is
In addition to the above-mentioned main functions, it detects the level of the transmitting signal coming from each channel, and for channels whose detection level is below a predetermined threshold, no transmitting is performed and the conference room of that channel is They often also have a mute function that blocks signals arriving from that channel, assuming that the channel is transmitting noise.

[Problem that the invention seeks to solve]

In the conventional conference call bridge device with the above-mentioned mute function, the signal arriving from the channel of the outgoing call is blocked in parts where the level is relatively low, such as the beginning or end of the outgoing call, resulting in a mute state. Therefore, there is a problem in that the beginning or end of a story is cut off in the signal sent back to another channel, making it difficult to hear the reproduced sound.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, it is an object of the present invention to provide a conference call bridge device which is capable of suppressing room noise in an incoming signal without cutting off the incoming signal and without cutting off the beginning or end of the incoming signal. It is about providing.

[Means for solving problems]

The device of the present invention is a conference call bridge device having an adding means for receiving input signals from a plurality of channels and returning a composite signal obtained by adding input signals other than the input signals for each channel to each channel, wherein each input signal is input to one input signal. a plurality of expanders that detect the level of the signal, amplify the input signal with a gain determined corresponding to the level, expand the level change of the input signal, and supply the expanded signal to the adding means; A plurality of compressors are provided, each of which has a level characteristic in which the gain sum is a predetermined value, and compresses the level change of the composite signal and then returns the resultant signal to one of the channels.

〔Example〕

Next, one embodiment of the present invention will be explained with reference to the drawings.

The first part is a block diagram showing an embodiment of the present invention, and FIG. 2 is a level characteristic diagram for explaining its operation.

In FIG. 1, input signals arriving from a plurality of channels CHI to C14m each pass through an expander 1, and then are sent to an adder 4 and guided to a subtracter 3 of the own channel. The expanders 1 of each channel are all syllabic expanders having the same level characteristics), and have the level characteristics of characteristic E illustrated by the solid line in FIG. Characteristic E means that the average level (input level) of the input signal is between Lm and L.
Between M (dBr), the gain increment changes in proportion to the input level increment, and the gain remains constant in the range where the input level is below Lm (dBr) or above LM (dBr). Each expander 1 detects the average level of the input signal, amplifies the input signal with a gain determined by the characteristic E according to the detection result, and transmits the amplified signal. The adder 4 adds all the signals given from the expander 1 of each channel, and sends the addition result to the subtracter 3 of each channel. The subtracter 3 of each channel generates a signal obtained by subtracting the output signal of the expander 1 of the own channel from the signal given from the adder 4, that is, a signal equal to the sum of the output signals of the expanders 1 of other channels than the own channel. is sent to the compressor 2 of its own channel.

The compressor 2 is a syllabic compressor having level characteristics such that the gain sum with the decompressor 1 is a predetermined constant value,
It detects the level of its own sending signal, and sends out a signal that is amplified with a gain determined according to the detection result as an output signal.

The level of the input signal of each channel is adjusted so that the average level during transmission is equal to a predetermined value. When not talking, room noise and the like arrive as input signals, but their average level is lower than when talking. In this embodiment, the difference between the average level of the input signal of the channel that is transmitting and the average level of the input signal of the channel that is not transmitting is determined by the expander 1.
After passing through, the expansion ratio increases to twice that of the expander 1.

For example, when the expansion ratio is 2, that is, in Fig. 2, the input level is (, t, o + p) (dBr) (however, Lm (
(Lo + i) < Lm), if the gain is (Go -) 1) (dB), the level difference between the input signal during transmitting and the input signal during non-transmitting increases by a factor of two after stretching. As a result, in the output signal of the adder 4, the input signal of the channel in use is emphasized, and the indoor noise of the channel in which the call is not made is suppressed relative to this. The compressor 2 amplifies the transmitted voice signal while maintaining its emphasis. Therefore, it emphasizes the transmitted voice signal, which has a relatively high level among the input signals of other channels, and eliminates room noise, etc., which has a relatively low level. A suppressed output signal can be obtained.

In this way, by emphasizing and bridging the one-to-one level difference between the input signals of each channel, it is possible to suppress room noise and the like without causing filler cuts or trailing cuts.

〔Effect of the invention〕

As explained above, the present invention has the effect that it is possible to realize a conference-to-call bridge device that can suppress room noise in an incoming signal without cutting off the incoming signal and without cutting off the beginning or end of the line. There is.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of AMJA according to the present invention, and FIG. 2 is a characteristic diagram for explaining the operation of the embodiment of the present invention. 1...Stretcher, 2...Pressure IIa device, 3
・・・・・・Subtractor, 4・・・・・・Adder. Agent Patent Attorney Susumu Uchihara Mini, Baka / Diagram

Claims (1)

[Scope of Claims] In a conference call bridge device having an adding means for receiving input signals from a plurality of channels and returning a composite signal obtained by adding input signals from channels other than the input signals for each channel, a plurality of expanders that detect the level of the signal, amplify the input signal with a gain determined corresponding to the level, expand the level change of the input signal, and supply the expanded signal to the adding means; and a plurality of compressors having level characteristics such that the sum of gains is a predetermined value and compressing level changes in the composite signal and returning the compressed signal to one of the channels. Call bridge device.