JPH0241933Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> The present invention relates to a volume control device that is included in televisions, stereos, etc. and controls the volume.

<Prior Art> Conventionally, the volume from a speaker provided in a television receiver, for example, has generally been adjusted by operating a volume adjustment knob provided on the front panel of the television receiver. However, images on a television receiver are usually viewed from a distance from the television receiver, and in such cases, the user must go to the television receiver each time to adjust the volume. The adjustment operation was extremely troublesome. To solve this problem, remote control devices have already been developed that allow the volume to be adjusted from a location away from the television receiver.

By the way, surrounding noise other than the sound from the speakers of the television receiver, such as people's voices and stereo sounds in the room adjacent to the room where the television receiver is installed, or the sounds of vehicles passing nearby, etc. is subject to change easily, and it is troublesome and troublesome to adjust the volume of the television receiver each time in response to changes in external noise, even when using a remote control device. It was hot.

<Purpose> The present invention has been made in view of the above points, and its purpose is to provide a volume control device that can automatically control the volume according to changes in external noise. shall be.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the present invention. In the figure, 1 is an audio signal level adjustment circuit, and this audio signal level adjustment circuit 1 adjusts the level of the audio signal to the optimum volume in response to a volume control signal given from a volume control signal forming circuit 2. adjust. The audio signal whose level has been adjusted by the audio signal level adjustment circuit 1 is sent to the amplifier 2'.
The signal is amplified by a speaker 3 serving as an audio output section, and is subjected to electroacoustic conversion and output as audio to the outside. When there is external noise, the sound output to the outside is detected together with the external noise by the microphone 4 as a detection means, and a detection signal that is a combination of the output sound and the external noise is output and sent to the amplifier. given to 5.

The amplifier 5 amplifies the output from the detection means 4 in response to the amplification control signal given from the AGC circuit 6. The AGC circuit 6 is supplied with an audio signal, and controls the amplification degree of the amplifier 5 so that the level of this audio signal matches the level of the audio signal component in the detection signal output from the amplifier 5. the amplifier 5 by forming an amplification control signal of
give to

The output from the amplifier 5 is given to an audio signal component cancel circuit 7. The audio signal component cancel circuit 7 is supplied with an audio signal, and outputs a comparison output corresponding to the difference between the output level of the amplifier 5 and the audio signal level, that is, an output corresponding to the external noise component in the detection signal. It is applied to the volume control signal forming circuit 2. The volume control signal forming circuit 2 forms a volume control signal to raise the volume if the level of the output corresponding to the external noise component from the audio signal component cancel circuit 7 is high, and to lower the volume if the output is low. It is applied to the signal level adjustment circuit 1. As a result, the audio signal level adjustment circuit 1 automatically adjusts the volume to the optimum volume according to the external noise.

FIG. 2 is a circuit diagram of the main part of the embodiment shown in FIG. The audio signal component cancel circuit 7 is
It is composed of an operational amplifier 8, and an audio signal is given to a minus input terminal, and a detection signal from the amplifier 5 is given to a plus input terminal. The operational amplifier 8 calculates both signals and generates a comparison output corresponding to the difference between the level of the detection signal and the level of the audio signal, that is, an output corresponding only to the external noise component with the audio signal component canceled, to form a volume control signal. Supply to circuit 2. To completely cancel the audio signal component,
It is necessary that the level of the audio signal component in the detection signal from the amplifier 5 and the level of the audio signal match.
Therefore, the AGC circuit 6 forms an amplification control signal for controlling the amplification degree of the amplifier 5 so that the level of the audio signal matches the level of the audio signal component in the output of the amplifier 5, and supplies it to the amplifier 5. this
The AGC circuit 6 is composed of a diode 9, an integrating circuit 10, and a variable resistor V _R. The applied audio signal is detected by the diode 9, converted to direct current by the integrating circuit 10, and then connected to the variable resistor V R. 11 and provides it to the amplifier 5 as an amplification control signal.

<Effects> As described above, according to the present invention, there is provided an audio signal level adjustment circuit that adjusts the level of an audio signal in response to a volume control signal, and an audio signal whose level has been adjusted by the audio signal level adjustment circuit. A volume control device comprising: an audio output section that electroacoustically converts the sound and outputs it to the outside as sound; a detection means that detects and outputs the sound output from the audio output section and external noise; an amplifier that amplifies in response to a control signal; an AGC circuit that forms an amplification control signal and outputs it to the amplifier so that the level of the audio signal matches the audio signal component level in the output of the amplifier; an audio signal component canceling circuit that outputs a comparison output corresponding to the difference between the level of the amplifier output and the level of the audio signal; and forming the volume control signal based on the output of the audio signal component canceling circuit to generate the audio signal. Since a volume control signal forming circuit is provided that outputs to the level adjustment circuit, the volume is automatically adjusted according to the level of external noise. There is no need to make any adjustments.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a circuit diagram of the main part of FIG. DESCRIPTION OF SYMBOLS 1...Audio signal level adjustment circuit, 2...Volume control signal formation circuit, 3...Speaker, 4...Microphone, 5...Amplifier, 6...AGC circuit, 7
...Audio signal component cancel circuit.

Claims (1)

[Scope of utility model registration request] an audio signal level adjustment circuit that adjusts the level of the audio signal in response to a volume control signal; and an audio output that electroacoustically converts the audio signal whose level has been adjusted by the audio signal level adjustment circuit and outputs it to the outside as audio. a detection means for detecting and outputting the sound output from the audio output section and external noise; an amplifier for amplifying the detection output in response to an amplification degree control signal; and an amplifier for amplifying the detection output in response to an amplification control signal; an AGC circuit that forms an amplification control signal and outputs it to the amplifier so that the level of the signal matches the level of the audio signal component output from the amplifier;
an audio signal component canceling circuit that outputs a comparison output corresponding to the difference between the level of the amplifier output and the audio signal; and forming the volume control signal based on the output of the audio signal component canceling circuit to control the audio A volume control device comprising: a volume control signal forming circuit outputting to a signal level adjustment circuit.