Analog summing and differencing circuit, optical receiving circuit, optical transmitting circuit, automatic gain control amplifier, automatic frequency compensation amplifier, and limiting amplifier

摘要

An analog circuit includes a pair of peak-hold circuits that generate peak signals indicating the peak values of a differential pair of input signals, a first differencing circuit such as a transconductance amplifier that takes the difference between the input signal values, a second differencing circuit such as a transconductance amplifier that takes the difference between the two peak signal values, and a combining circuit such as a resistor circuit that additively combines the outputs of the differencing circuits in such a way as to compensate for direct-current offset in the input signals. Advantages of this circuit structure include reduced power consumption and simplified implementation in an integrated circuit. Low pass filters, capacitor discharging circuits, and unbalanced circuit elements can be used to obtain further advantages.