四、限幅电路 限幅电路的作用是消除噪声或引擎引起的调幅分量,将中放输出的信号限制在一个固定的电平上,一般有利用二极管的非线性来使输出信号振幅限制在一定值上的二极管限幅器,利用晶体管的截止和饱和特性使输出信号幅度不变的晶体管限幅器;用电流限流型分差放大器限制输出电流为一定值的限流式限幅电路等。 Fourth, the limiter circuit The role of the limiter circuit is to eliminate the noise or engine-induced amplitude modulation component, the signal output in the limit to a fixed level, the general use of the diode to limit the output signal amplitude non-linearity A diode limiter on the value, a transistor limiter that makes use of the transistor’s cut-off and saturation characteristics to keep the amplitude of the output signal constant, a current-limited limiter circuit that limits the output current to a certain value by using a current-limited differential amplifier.