AUTOMATIC GAIN CONTROLLER

摘要

PURPOSE: An automatic gain controller is provided to have a higher dynamic range without losing the performance against adjacent channel disturbance and intermodulation distortion disturbance. CONSTITUTION: In an automatic gain control amplifier(AGCa), an RF automatic gain controller(2) controls a gain of a wireless frequency band signal(Srf). Frequency converters(3,4) convert a signal(Srfa) with a wireless frequency band into a signal(Sifa) with an intermediate frequency band. An IF automatic gain controller(5) controls a gain of the intermediate frequency band signal(Sifa). A level detector(Lda) detects a signal level of the intermediate frequency band signal(Sifa) to generate a level signal(Sla). Automatic gain control signal generators(Sga,SGb) control the IF automatic gain controller(5) and the RF automatic gain controller (2) individually on the basis of level signals(SLa,SLb).