Patent ID: 6078224
Filing Date: 2000-06-20
Classification: G04R,H03L

Abstract:
A frequency standard generator for generating an high accuracy reference frequency signal, comprising:a voltage controlled crystal oscillator (VCXO) for generating high stability output signal to be used as a standard frequency signal;a radio wave receiver which receives a radio wave which includes a high accuracy time signal and reproduces a 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 time signal and said output signal of said VCXO and generates data indicating said phase difference (""phase difference data"");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 phase controller which monitors an average phase difference between the output signal of said VCXO and said time signal and initiates a phase control operation for reducing the average phase difference for a predetermined period of time by generating phase compensation data; anda D/A converter which converts said control data from said frequency control processor or said phase compensation data from said phase controller to an analog voltage to be provided to said VCXO.