Patent ID: 6081163
Filing Date: 2000-06-27
Classification: G01S,G04G,G04R,H03L

Abstract:
A standard frequency and timing generator for generating a high accuracy standard frequency signal and a timing signal, comprising:a voltage controlled crystal oscillator (VCXO) for generating high stability output signal to be used as a standard frequency and timing signal;a radio wave receiver which receives a radio wave which includes a high accuracy reference time signal and reproduces said time signal to be used as a reference for said VCXO;a time interval measuring circuit which measures a time interval which is a phase difference between said reference time signal and said output signal of said VCXO and generates data indicating said phase difference;a frequency control processor which arithmetically determines control data based on said phase difference data from said time interval measuring circuit such that said phase difference maintains a constant value by a phase lock loop;a frequency deviation data generator for averaging and compiling said phase difference data with a predetermined sequence to obtain frequency deviation trend data of said VCXO;a compensation data generator for generating compensation data based on said frequency deviation trend data to compensate frequency changes in said VCXO when said reference time signal is unavailable for said phase lock loop;a reference signal detector for generating a detection signal when said reference time signal is unavailable from said radio wave receiver for said phase lock loop; anda D/A converter which converts said control data from said frequency control processor and said compensation data from said compensation data generator to an analog voltage to be provided to said VCXO.