DIGITAL QUADRATURE DEMODULATION DEVICE WHOSE DC OFFSET IS CONTROLLED

摘要

PURPOSE: A digital quadrature demodulation device is provided where its DC offset is effectively controlled without increasing a complexity while realizing a hardware. CONSTITUTION: An A/D(Analog/Digital) converter(10) receives a receiving signal, and a matching filter(11) receives an output of the A/D converter. A digital interpolation filter(12) receives an output of the matching filter and an output of a symbol timing recoverer(14). A carrier phase detector(13) receives an output of the digital interpolation filter and an output of a carrier recoverer(15). A signal determination part(16) receives an output of the carrier phase detector, and the symbol timing recoverer receives the output of the carrier phase detector and an output of the signal determination part. The carrier recoverer receives the output of the carrier phase detector and the output of the signal determination part. And a DC offset control part(20) receives a recovery signal and a determination signal(symbol). The DC offset control part comprises a DC offset detector(21) receiving the recovery signal and the determination signal, and a loop filter(22) receiving an output of the DC offset detector, and a D/A converter(23) receiving an output of the loop filter.