Audio squelch system with hysteresis comparison circuit

Abstract

The invention provides an audio squelch system with a hysteresis comparison circuit. The system comprises an early warning signal terminal, an on-off control terminal, a digital logic control circuit, a first charge-discharge signal judgment terminal, a digital delay circuit, a digital logic combination circuit, a second charge-discharge signal judgment terminal, a common mode voltage generation circuit, an RC (resistor-capacitor) charging resistor, a reference voltage terminal, a charge-discharge curve generation circuit, the hysteresis comparison circuit, a charge-discharge capacitor and a common mode voltage output terminal, wherein the digital logic control circuit generates a charge-discharge finish judgment signal to the first charge-discharge signal judgment terminal; and the digital delay circuit and the digital logic combination circuit delay judgment signals sent by the first charge-discharge signal judgment terminal and generate a final charge-discharge finish judgment signal to the second charge-discharge signal judgment terminal after the hysteresis comparison circuit finishes working. The system can be used for effectively suppressing POP noise.

Description

technical field [0001] The invention relates to an audio processing system, in particular to an audio squelch system with a hysteresis comparator circuit, which has a simple structure, can eliminate offset voltage generated in the system, and can suppress POP noise. Background technique [0002] POP noise refers to the noise generally present in the audio system during startup and shutdown. [0003] When the audio system is turned on, the input and output voltage of the audio system needs to be rushed to the common mode voltage, and when the power is turned off, this voltage needs to be reduced to 0. When the charging and discharging voltage reaches the required voltage, it needs to switch to the normal mode. mode to provide common-mode voltage, so in the process of common-mode voltage switching, offset voltage will inevitably be generated, so it is easy to cause impact on the speaker or earphone driven by the driver when the power is turned on and off to form POP noise, and...

AI Technical Summary

Problems solved by technology

[0003] When the audio system is turned on, the input and output voltage of the audio system needs to be rushed to the common mode voltage, and when the power is turned off, this voltage needs to be reduced to 0. When the charging and discharging voltage reaches the required voltage, it needs to switch to the normal mode. mode to provide common-mode voltage, so in the process of common-mode voltage switching, offset voltage will inevitably be generated, so it is easy to cause impact on the speaker or earphone driven by the driver when the power is turned on and off to form POP noise, and let the uncomfortable for sensitive ears

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