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快速而精确的自动增益控制(AGC)放大器可以用一个压控放大器(VCA)和一个单电源电压反馈放大器配置成积分器来产生(图1).AD603VGA具有“线性(dB)”传递函数.将差分增益控制电压(G_(pos)-G_(neg))从-0.5V改变到+0.5V,则放大器增纹.VCA输出信号的dC表示产生的电流I_(xy),经一10k电阻流入AD8041运放的反相节点(Y).大约—1V的参考电压使一恒流从此节点流经另一个10k电阻(包含在此参考电路的二极管补偿整流二极管的漂移).这些电流(I_(int))之间的差值流经积分器电容.
A fast and accurate automatic gain control (AGC) amplifier can be configured as an integrator with a voltage-controlled amplifier (VCA) and a single supply voltage feedback amplifier (Figure 1). The AD603VGA has a “linear” (dB) transfer function. The differential gain control voltage (G_ (pos) - G_ (neg)) changes from -0.5V to +0.5 V, then the amplifier is textured. The dC of the VCA output signal represents the resulting current I xy flowing through a 10k resistor into the AD8041 The inverting node (Y) of the op amp. A reference voltage of approximately -1V causes a constant current to flow from this node through another 10k resistor (the diode contained in this reference compensates for the drift of the rectifier diode.) These currents (I_ (int) ) The difference between the values flows through the integrator capacitor.