一:用模拟乘法器构成的自动增益控制器: 图1是一个自动增益控制器(AGC)电路,它由一个四象限模拟乘法器IC_1、放大器IC_2、全波整流器(D_1、D_2,R_4—R_7和IC_3组成)、积分器IC_4构成,完成声频范围内V_(IN)幅度变化的自动增益控制。乘法器的输出是—V_(IN) V_Y/10,式中V_Y是积分器IC_4产生的负电压。同时,积分器和整流器取出输出电压V_(cut)的直流成分V_Y作乘法器的反馈信号。积分 A: Automatic Gain Controller with Analog Multiplier: Figure 1 shows an Automatic Gain Controller (AGC) circuit consisting of a four-quadrant analog multiplier IC_1, an amplifier IC_2, a full-wave rectifier (D_1, D_2, R_4-R_7 And IC_3), and integrator IC_4 to complete the automatic gain control of V_ (IN) amplitude variation in the audio frequency range. The output of the multiplier is -V_ (IN) V_Y / 10, where V_Y is the negative voltage generated by integrator IC_4. At the same time, the integrator and rectifier take out the DC component V_Y of the output voltage V cut as the feedback signal of the multiplier. integral