Abstract: Traditional approaches of AGC acquire error control signals by estimating the average value over a long period of time. It results in complicated circuitry and is susceptible to intersymbol interference. In this paper, we present an equalizer based AGC approach that uses the equalizer’s error to adaptively compensate for the input signal and effectively reduces the complication of the hardware. Simulation results demonstrate good acquisition and tracking performances under circumstances of degraded signal. |Keywords： automatic gain control (AGC); equalizer; intersymbol interference