Carrier tracking circuit for IQ demodulator

摘要

The carrier tracking circuit uses a voltage controlled oscillator (4), providing a complex output signal (A) fed to the demodulator (3) for converting the input signal (IF) into a baseband signal (B), fed to a decision stage (5) for recovery of the transmitted data sequence. A phase detector (15) compares the baseband signal with a reference signal obtained from the recovered data sequence, for phase and frequency regulation of the oscillator. A filter (12) is inserted between the output of the decision stage and the input of the phase detector, for simulation of the transmission and reception filters and the transmission path.