自动增益控制(AGC)电路在自动化及数字通信等方面得到了广泛应用。图1所示就是一个典型的带反馈结构的AGC电路,它的目的是在输出端y(t)保持恒定的能量电平。输出信号馈入全波整流器并经过滤波后产生一个信号能量的估算值E(t),减法器将这个信号能量的估算值与预选参考值进行比较,产生的差分信号,通过控制电路改变放大器的增益,将E(t)与E_RET尽可能保持一致。图2所示AGC Automatic Gain Control (AGC) circuits are widely used in automation and digital communications. Figure 1 shows a typical AGC circuit with a feedback structure whose purpose is to maintain a constant energy level at output y (t). The output signal is fed into a full-wave rectifier and filtered to produce an estimate of the signal energy, E (t). The subtractor compares the estimate of this signal energy with the preselected reference value to produce a difference signal, which is changed by the control circuit Gain, keep E (t) as close as possible to E_RET. Figure 2 shows the AGC