Patent ID: 6392479
Filing Date: 2002-05-21
Classification: H03G,H03M

Abstract:
An automatic gain controller having variable gain amplifiers of a plurality of systems and the corresponding control loops, comprising:a gain control signal generator which generates a gain control signal that controls a variable gain amplifier based on the output signal level of the variable gain amplifier; a variation amount detector which detects the variation amount of the output signal level; a level comparator which compares the output signal levels of the plurality of system with each other; an inter-control-loop correction section which generates a correction gain control signal that corrects variations in the circuit characteristics of the other control loops and that is based on a gain control signal in the control loop where the output signal level is the highest in order to perform gain control; and an operation controller which selects the control loop where the output signal level is the highest, places the gain control signal generator for the other control loops in the non-operating state, and performs gain control of the variable gain amplifiers of the plurality of systems via the gain control signal in the control loop where the output signal level is the highest and correction gain control signals in the other control loops, in case the variation amount in the output signal level is smaller than a predetermined value.