AFC circuit of digital demodulation device

摘要

A phase detection circuit (15) detects a phase of a phase detection signal output from a complex multiplication circuit (13). A frequency error detection circuit (16) detects a frequency error of a phase-detected signal, with the first frequency error detection characteristic in which a first frequency domain is defined as a detection range. An average circuit (17) converts a signal having the detected frequency error into a signal having a second frequency error detection characteristic in which a second frequency domain other than the first frequency domain is defined as a detection range. After the average circuit calculates an average of frequency error signals for each period of time, it converts an average signal into a signal having the original first frequency error detection characteristic and outputs it toan AFC loop filter (18). <IMAGE>