Title:
【発明の名称】基準周波数発生装置
Document Type and Number:
Japanese Patent JP3085511
Kind Code:
B2
Abstract:
A frequency standard generator includes a voltage controlled crystal oscillator for generating high stability output signal to be used as a standard frequency signal, a satellite wave receiver which receives a radio wave from a satellite which includes a highly accurate satellite time signal and reproduces the satellite time signal to be used as a reference for the voltage controlled crystal oscillator, a frequency divider which divides the output signal of the voltage controlled crystal oscillator by a dividing ratio arranged to generate a crystal time signal which is identical in frequency to the satellite time signal, a time interval measuring circuit which measures a time interval which is a phase difference between the satellite time signal and the crystal time signal and generates a digital signal indicating the phase difference, a frequency control processor which arithmetically determines control data based on the digital signal from the time interval measuring circuit such that the phase difference maintains a constant value through an operation of a phase lock loop, and a D/A converter which converts the control data from the frequency control processor to an analog voltage which is used to control the output frequency of the voltage controlled crystal oscillator.
Inventors:
Hitoshi Ujiie
Application Number:
JP31419294A
Publication Date:
September 11, 2000
Filing Date:
November 24, 1994
Export Citation:
Assignee:
Advantest Corporation
International Classes:
G04G3/00; G01S19/14; G04R20/00; G04R20/02; G04R40/00; H03L7/06; H03L7/093; H04L7/033; G01S1/00; H03L1/02; (IPC1-7): H03L7/06; G01S5/14; G04G3/00; G04G7/02; H04L7/033
Domestic Patent References:
| JP5167485A | ||||
| JP648728A | ||||
| JP631977A | ||||
| JP6232740A | ||||
| JP61119416U |