Echo suppression and howling prevention voice intercom system based on program control electronic attenuator

Abstract

The invention discloses an echo suppression and howling prevention voice intercom system based on a program-controlled electronic attenuator. A signal processing module is formed by a pre-amplifier A, an attenuator A, a power amplifier A, a pre-amplifier B, an attenuator B, a power amplifier B and a single chip microcomputer, and a voice amplification signal A output by the pre-amplifier A and a voice amplification signal B output by the pre-amplifier B are acquired and are compared with the normal range of the voice signal to judge whether howling exists or not, and howling suppression and echo suppression can be realized by performing logic control on the attenuator A and the attenuator B when howling exists; and the system has the advantages of high environmental adaptability, capability of realizing full-duplex call, no need of mastering a complex digital filter algorithm, lower application threshold, lower operand, no need of DSP processing, capability of processing by a simple single chip microcomputer and low scheme cost.

Description

technical field [0001] The invention relates to an echo suppressing and howling-preventing voice intercom system, in particular to a program-controlled electronic attenuator-based echo suppressing and howling-preventing voice intercom system. Background technique [0002] The voice intercom system is used for two-way voice communication between two rooms. It mainly includes two electro-acoustic conversion modules and a signal processing module. Each electro-acoustic conversion module includes a microphone and a speaker, and the two electro-acoustic conversion modules One-to-one correspondence is set in two rooms. The two rooms are respectively called room A and room B, and the two electroacoustic conversion modules are respectively called electroacoustic conversion module A and electroacoustic conversion module B, wherein the electroacoustic conversion module A includes a microphone A and a speaker A, and the electroacoustic conversion module Module B includes microphone B ...

AI Technical Summary

Problems solved by technology

Since the microphone and speaker in the same room cannot achieve sound isolation, the following problems will occur in the voice intercom system: (1) Echo: the sound received by microphone A is processed by the signal processing module and then transmitted to speaker B for playback, and the sound will be The microphone B is received, and then returned to the speaker A through the signal processing module to play, and the signal is looped back to generate an echo; the same is true for calls in the opposite direction

The above-mentioned first solution is low in cost, high in chip integration, and simple in application, but it has the following disadvantages: 1. It can only be half-duplex, that is, calls in one direction will prevent calls in the other direction; 2. Poor environmental adaptability and noisy In the environment, or when the sound source is far away from the microphone, the system cannot work normally, and abnormal phenomena such as intermittent sound occur; 3. The parameters of the resistance device around the dedicated chip need to be matched according to the application scenario, and it is difficult to debug and optimize

The above-mentioned second solution uses audio signal processing algorithms to suppress the spectral components that may cause howling and echo, and realizes full-duplex communication, and the software automatically recognizes the distance between the sound source and the microphone, automatically controls the gain, and has strong environmental adaptability. It has the following disadvantages: 1. High CPU overhead and high cost; 2. High software algorithm complexity and high application threshold

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