PHASE NOISE REDUCTION CIRCUIT, PHASE MODULATOR, PHASE DEMODULATOR AND HIGH-FREQUENCY COMMUNICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a phase noise reduction circuit, a phase modulator and a phase demodulator which effectively reduce phase noise from an oscillator with a simple configuration, allow a multi-stage connection without disturbing the operation of the phase noise reduction circuit such as PLL circuits, and to provide a high-frequency communication system which reduces phase noise mixing in from a local oscillator and improves communication quality.;SOLUTION: A semiconductor limiter circuit 5 limits the power level of an input signal. A power level phase adjusting circuit 6a adjusts the power level and the phase of a signal which passes through the limiter circuit 5 and a power level phase adjusting circuit 6b adjusts the power level and the phase of the input signal. A power combiner 4 combines the signals having the power levels and the phases adjusted by the adjusting circuits 6a, 6b and outputs a signal, thus canceling phase noise components to extract only the sinusoidal signal components.;COPYRIGHT: (C)2003,JPO