CARRIER WAVE CONTROL LOOP FOR RECEIVER OF DIGITAL TRANSMISSION SIGNAL

摘要

PROBLEM TO BE SOLVED: To provide a carrier wave control loop that can reduce the sensitivity for an interference with a receiver of a digital transmission signal. SOLUTION: This device is a carrier wave control loop 1 that is equipped with a quadrature phase signal demodulator 3 vertically arranged in the direction in which the signal flows, a code identification device 4, a detector 9 for generating at least either of a phase deviation value or a frequency deviation value, a feedback device 10 and a variable frequency oscillator 11 connected to the quadrature phase signal demodulator. An evaluation device 12 is added to this device and this evaluation device 12 decides a value of reliability of at least one of each phase deviation value and the frequency deviation value measured by the detector from the signal of the carrier wave control loop, and characteristically controls the carrier wave control loop according to the decided value of reliability. The evaluation device 12 evaluates a phase value and/or the absolute value formed by a resolver 8 from the quadrature phase element and an equiphase element generated by the quadrature phase signal demodulator 3.