ADAPTIVE FREQUENCY PHASE DETECTION SYSTEM FOR REDUCING PHASE NOISE AND REDUCING METHOD THEREOF, ESPECIALLY USING LIMITER OUTPUT OF PLL

摘要

PURPOSE: An adaptive frequency phase detection system is provided to increase an S/N ratio of a recovered signal and reduce an error rate by adaptively a point of convergence of a frequency according to an input signal. CONSTITUTION: A complex frequency multiplier(304) is used for performing a complex frequency multiplication process for a received pilot signal and an oscillation signal. A phase converter(305) is used for converting a phase of a real part of an output signal from the complex frequency multiplier. A limiter(306) is used for limiting an output signal of the phase converter. A synchronous detector(307) is used for detecting a synchronous convergence. A mode selector(310) is used for limiting selectively a band of an imaginary part by using the synchronous convergence as a control signal. A multiplier(311) is used for multiplying an output of the limiter by an output of the mode selector.