JPH05145990A - External noise identification sensor - Google Patents

Abstract

PURPOSE:To provide the external noise sensor which can satisfactorily discriminate the reqroducing sound of an audio reproducing equipment itself and external noise. CONSTITUTION:Volume level change circuits 1, 3 are respectively provided for an audio signal 15 reproduced by the equipment and a signal 16 detected by a microphone 10. Then, a controlled output only to the external noise is obtained by a comparator 5 and an integrator 6 to smooth the rapid change.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for reproducing audio signals.

[0002]

2. Description of the Related Art In recent years, the number of home electric appliances having a function corresponding to the environment has been increasing.

A sensor that senses the state of the environment is required to have a function corresponding to the environment, and a simple microphone (hereinafter referred to as a microphone) is used in the device to sense the sound.
Will be installed.

[0004]

However, it is not possible to determine whether the sound sensed by the microphone is the sound of the device itself or the external sound by only mounting the microphone in this way, and therefore the device is reproduced against external noise. There was a problem that the purpose of adjusting the sound could not be achieved.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a sensor for adjusting the reproduced sound of a device only for external noise.

[0006]

In order to achieve the above object, the present invention, as shown in FIGS. 1 and 2, converts the volume level of a voice signal to be reproduced by a device and the volume level of a signal detected by a microphone. , A level adjusting circuit for making the difference between the two outputs zero when there is no extraneous sound (there is also a case where either one may be omitted), a comparator for both outputs, It has an integrator to prevent it from reacting to sudden sounds.

The audio signal to be reproduced by the device and the signal detected by the microphone are made to have a difference after being converted into a volume level, but the microphone is picked up even if the difference is made without conversion. Since the reproduced sound of the device has different phase and frequency characteristics, it cannot be canceled. If you convert it, you can almost cancel it regardless of some differences.

[0008]

According to the present invention, the voice output can be changed according to only the external noise by the above structure.

[0009]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a circuit block diagram showing a first embodiment of the present invention. Two level adjusting circuits 2 and 4 are adjusted so that the subtraction result becomes zero when there is no extraneous sound. When extraneous noise comes in, a difference appears in the volume level, and the subtraction result is not zero. The external sound is generally irregular, and when it is very sudden, it is unnatural when the reproduction output changes, so the change is smoothed by the integrator 6, and then the output is superimposed on the volume control voltage. Then, the playback output of the device increases correspondingly. When the reproduced sound becomes louder, the signal to the microphone becomes louder and the positive feedback is applied. However, when the level of the external sound becomes negligible, the steady state is reached.

FIG. 2 is a circuit diagram of a second embodiment of the present invention, in which a comparator is used as a comparator (hence the integrator is changed to the input side), and its output voltage suppresses volume change.
We are opening and closing 4. This circuit enters when there is extraneous noise, and the function of this circuit makes it possible to prevent the small portion of the reproduced sound from becoming large and masking by extraneous noise.

[0012]

As is apparent from the above embodiments, according to the present invention, the voice can be controlled only by the external noise, and the sensor in which the influence of the reproduced sound of the device itself is well removed can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a block diagram of a second embodiment of the present invention.

[Explanation of symbols]

 1 volume level conversion circuit 2 level adjustment circuit 3 volume level conversion circuit 4 level adjustment circuit 5 comparator 6 12 13 integrator 7 adder 8 volume control IC 9 power amplifier 10 microphone 11 speaker 14 compressor 15 audio that the device is going to reproduce Signal 16 Signal detected by the microphone

Claims (2)

[Claims] 1. A circuit for converting an audio signal reproduced by a device itself into a volume level thereof, and a circuit for converting a signal output from an external noise sensor mounted in the device into the volume level thereof. External noise identification sensor that can change the volume of the device according to the difference when there is a difference. 2. An external noise having the two circuits according to claim 1, wherein a circuit (compressor) for reducing a volume change of a reproduced voice is turned on and off according to a difference between outputs of the two circuits. Identification sensor.