一种可变增益的音频放大电路设计及实现

Design and implementation of a variable gain audio amplifier circuit

针对音频设备应用,需要对动态范围大的声音信号进行预处理,使声音信号维持在一个合理的幅度内,保证声音输出的良好效果,以避免由于信号过大造成后级电路产生严重失真损坏音质,或信号过小受到噪声干扰使声音淹没等现象。文中提出了一种可自动控制增益的音频放大电路,该电路主要由前置放大电路、峰值检测器、阈值检测模块、可变增益放大器构成,可以实现20 Hz~20 kHz的自动增益控制。

For the application of audio equipment,it is necessary to preprocess the sound signal with large dynamic range,so that the sound signal can be maintained in a reasonable amplitude and good sound output effect can be guaranteed.In order to avoid overall equipment damage caused by serious distortion in the subsequent circuit and damage the sound quality,or the signal is too small to be disturbed by noise and drown the sound signals.An audio amplifier circuit with automatic gain control is presented.It is mainly composed of pre-amplifier circuit,peak detector,threshold detection module,variable gain amplifier.It can realize the automatic gain control of 20 Hz~20 kHz.