Supporting circuits with a single local oscillator

Abstract

A digital signal processing circuit includes an analog gain compensator that compensates for an analog gain of a baseband signal including a plurality of component carriers (CCs) to output a compensated baseband signal; an analog-to-digital converter (ADC) that converts the compensated baseband signal into a first digital signal; a plurality of filtering circuits that generate a second digital signal from the first digital signal; and a control circuit. Each filtering circuit sequentially filters the first digital signal so that a corresponding one of the second digital signals retains one CC among the CCs, compensates for a digital gain, and a performs down-sampling. The control circuit generates an analog gain control signal for controlling the analog gain based on the second digital signals and a digital gain control signal for controlling the digital gain.