Variable gain control circuit and receiver apparatus using the circuit

摘要

Disclosed is a variable gain control circuit for executing automatic-gain-control on a variable gain amplification block composed of a plurality of amplifiers on which discrete gain setting is executed by a programmable-gain-amp method. A baseband amplifier is composed of a plurality of amplifiers on which discrete gain setting is executed by a programmable-gain-amp method. A programmable-gain-amp control processing block references a programmable-gain-amp control data table on the basis of a difference between a current receive signal level and a predetermined receive signal level to determine the gain of the baseband amplifier. A programmable-gain-amp control processing block references a direct-current offset cancel table on the basis of current programmable-gain-amp data and next programmable-gain-amp data to generate corresponding direct-current offset cancel data, converts the generated direct-current offset cancel data into an analog voltage, and adds the analog voltage to the baseband amplifier output.