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一、引言在电路系统中,有时需要将某一信号进行限幅放大。限幅放大的传统方法是将信号通过一个非线性放大器,利用元器件的饱和特性达到限幅的目的。图1为一典型的限幅电路,信号ν_1以R_1/R_1的放大倍数放大,当ν_0的幅值到达稳压管D_1、D_2的导通值时,ν_0被限定在D_1、D_2的导通值上,成为梯形波。这样不管输入信号幅值多大(只要不超过运算放大器的允许输入电压),输出电压总被限制在一定的幅值上。很显然,信号经过这样限幅以后,变得严重失真了,对于某些电路这是无关紧要的,而有些电路却是不允许的。在这种情况下,我们只能采用滤波的办法,滤掉高次谐波来保持原信号的形状,可是这种方法有两个
First, the introduction In the circuit system, sometimes need to limit the amplification of a signal. The traditional method of limiting amplification is to pass the signal through a non-linear amplifier, using the saturation characteristics of components to achieve the purpose of clipping. Figure 1 shows a typical limiting circuit. The signal ν_1 is amplified by the amplification of R_1 / R_1. When the amplitude of ν_0 reaches the turn-on value of the regulator D_1, D_2, ν_0 is limited to the turn-on value of D_1, D_2 On, become trapezoidal wave. In this way, the output voltage is always limited to a certain amplitude regardless of the magnitude of the input signal (as long as it does not exceed the allowable input voltage of the operational amplifier). Obviously, the signal becomes severely distorted after such clipping, which for some circuits is irrelevant, while others are not allowed. In this case, we can only use the filtering method, filter out higher harmonics to maintain the shape of the original signal, but this method has two