JPS6223132Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an automatic multi-channel input audio mixing device used in conference microphone systems and other multi-channel input circuits.

BACKGROUND ART A conventional multi-channel input audio automatic mixing device, as shown in FIG. The variable circuit 5,
6 is guided to an output terminal 8 through a mixer circuit 7, and taken out as an output.
In this case, when controlling the variable circuits 5 and 6, the outputs amplified by the amplifiers 3 and 4 are applied to the input circuits 9 and 10 each having an envelope detection function, and the outputs are compared by the differential amplifier 11. , the amplifier 1
1 output is the preset 1st and 2nd set value +
The comparator 12 compares whether it is larger or smaller than T and -T, and depending on the output, the output of the amplifier 3 is supplied to the output terminal 8 through the mixer circuit 7, or the output of the amplifier 4 is supplied to the output terminal 8 through the mixer 7. The variable circuits 5 and 6 for supplying the signal to the output terminal 8 are controlled. Note that 13 is an inverter.

Problems to be Solved by the Invention However, in this type of mixing device, when comparing whether the output of the amplifier 11 has become larger or smaller than a preset value, the comparator 12 uses the first and second set values. +T, -T are provided,
Since so-called hysteresis is provided, once the input signal is switched to appear at the output terminal 8 through one audio input system, if there is no considerably large input to the other audio input system, the system switches to the other audio input system. This resulted in the problem that topics would always go out of topic when switching between the two.

The present invention eliminates the above-mentioned drawbacks of the conventional system, and gives priority to at least one audio input system that is in charge of the moderator, etc., and that audio input system is given priority over other audio input systems, even if the input is relatively small. It is an object of the present invention to provide an excellent multi-channel input audio automatic mixing device that can sufficiently switch to the audio input system.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides an audio transmission system in which any one of a plurality of audio transmission systems and the input of this audio transmission system and the input of other audio transmission systems are mutually connected. A DC bias circuit is provided between the comparators that apply a DC bias to the input of any one of the audio transmission systems, so that even if the input of any one of the audio transmission systems is relatively small, This configuration is such that the input of the audio transmission system is guided preferentially to the output terminal.

Effect Therefore, according to the present invention, any one of the above
If one audio transmission system is used as the audio transmission system for the person in charge of the moderator, etc., it is possible to almost completely prevent the person in charge of the moderator, etc. from cutting off at the beginning of the conversation, and to provide an excellent multi-channel input audio automatic mixing device. I can do it.

Embodiment FIG. 2 is a schematic diagram of an embodiment of the present invention. In FIG. 2, numerals 1 to 12 indicate the same components as shown in FIG. 1. Reference numeral 14 indicates a DC bias circuit composed of a resistor 141 and a DC power supply 142, 15 a timer, and 16 a NAND gate.

In FIG. 2, inputs applied to input terminals 1 and 2 are amplified by amplifiers 3 and 4, respectively, and applied to variable circuits 5 and 6, respectively. Then, a part of it is applied to each input terminal of the differential amplifier 11 through input circuits 9 and 10. By the way, in this case,
A DC bias circuit 14 is provided on the input side of the input circuit 9, so that a DC bias is superimposed on one input that is input to the input terminal 1 and amplified by the amplifier 3. Therefore, the differential amplifier 11 has a signal applied to the input terminal 1 and amplified by the amplifier 3, to which the DC bias of the DC bias circuit 14 is added, and a signal applied to the input terminal 2 and amplified by the amplifier 4. The signals are compared with each other, and a signal corresponding to the difference between the two is output. It will be compared whether it is larger or smaller. Since the variable circuits 5 and 6 are controlled by the output of the comparator 12, even if the input applied to the input terminal 1 is relatively small, the input applied to the input terminal 1 is preferentially guided to the output terminal 8 through the variable circuit 5.

In this way, according to the above embodiment, the input of one of the audio transmission systems can be guided to the output terminal preferentially, and in this system, the occurrence of interruptions at the beginning of speech can be significantly reduced. Further, according to the above embodiment, a timer 15 and a NAND gate 16 are provided after the comparator 12.
An operation extension circuit consisting of the following is provided, and therefore, it is possible to almost eliminate endings of speech in the other audio transmission system. That is, in the above embodiment, the input now applied to input terminal 2 is applied to input terminal 1.
Assume that the comparator 12 outputs a signal which is sufficiently larger than the input applied to the input signal and which reduces the amount of loss in the variable circuit 6 and increases the amount of loss in the variable circuit 5, as shown in FIG. In this state, if a large input is applied to the input terminal 1, the comparator 12 will of course
The output of the timer 1 is inverted and switched to a signal that increases the loss amount of the variable circuit 6 and reduces the loss amount of the variable circuit 5. In this case, according to the above embodiment, the timer 1
5. Due to the action of the NAND gate 16, as shown in _FIG . This has the advantage that it is possible to almost eliminate endings of words in the voice transmission system.

Effects of the invention As is clear from the above embodiment, the present invention provides a DC bias circuit in a specific audio transmission system, and increases the apparent height of the input of that transmission system to compare it with the input of other transmission systems. It is configured as follows,
Therefore, it has the advantage that priority can be given to the specific audio transmission system, and it can be effectively used as an audio transmission system for a person in charge of a moderator or the like.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional multi-channel input audio automatic mixing device, Fig. 2 is a block diagram of a multi-channel input audio automatic mixing device according to an embodiment of the present invention, and Fig. 3 is a partial operation of the same device. FIG. 1, 2...Input terminal, 3, 4...Amplifier, 5,
6...Variable circuit, 7...Mixer circuit, 8...Output terminal, 9, 10...Input circuit, 11...Differential amplifier, 12...Comparator, 14...DC bias circuit, 15...Timer , 16...Nand Gate.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A variable circuit that can control the amount of loss for each of a plurality of audio transmission systems that transmit signals for mixing, and a comparison of the inputs applied to each of the audio transmission systems,
A control means for controlling the amount of loss in the variable circuit is provided so that only the audio signal having a higher audio input level is guided to the output terminal, and a DC bias is applied between any one of the audio transmission systems and the control means. A multi-channel input audio automatic mixing device configured to include a circuit and give priority to the audio transmission system. (2) The automatic multi-channel input audio mixing device according to claim 1, wherein at least one of the variable circuits controlled by the control means is provided with a timer circuit for extending the operation for a certain period of time. (3) The multi-channel input audio automatic mixing device according to claim 2, wherein the timer circuit is provided between the variable circuit on the side not having the DC bias circuit and the control means.