Patent ID: 6996386
Filing Date: 2006-02-07
Classification: H03G

Abstract:
1. An automatic gain control circuit controlling a gain of a receiver including a first a first automatic gain control amplifier amplifying a RF signal and a second automatic gain control amplifier amplifying an IF signal, comprising: an operation circuit performing addition on a value of an adjustment signal variably adjustable in a prescribed range and a reference value of a power of an input signal input into the receiver, to calculate a difference value between a result of the addition and the power of the input signal input into the receiver; a control signal adjustment circuit adjusting a value of a control signal controlling a gain of said first automatic gain control amplifier and a gain of said second automatic gain control amplifier, based on said difference value; and a control circuit, including a circuit to variably adjust a value of said adjustment signal, a circuit to acquire a bit error rate after demodulation of the input signal input into the receiver, a circuit to store the value of said adjustment signal and a bit error rate changed as a result of control of the gains of said first automatic gain control amplifier and said second automatic gain control amplifier by the value of the adjustment signal in association with each other, and a circuit to identify a value of the adjustment signal with a minimum bit error rate in said values stored in association with each other, and fixing the value of the adjustment signal input into said operation circuit to said identified value.