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Patent Searching and Data


Title:
PHASE MEASURING CIRCUIT
Document Type and Number:
Japanese Patent JPH02298872
Kind Code:
A
Abstract:

PURPOSE: To measure a phase with high accuracy by operating the frequency of the input recorded on a shift register and detecting the phase of said input on the basis of sine and cosine local signals same in frequency and becoming 0 in a phase angle at a measuring time.

CONSTITUTION: The input subjected to A/D conversion is taken in a shift register 7. From the point of time when an N-clock delay gate 5 becomes effective by a sampling pulse showing a phase measuring time, the register 7 of the (2N+1)-th stage stores (N) data at the sampling time and before and after said time. At first, a wave number counter 8 counts zero cross from the data of the register 7 and an operator 9 operates input frequency on the basis of the count value. Next, a (2N+1) local phase wherein the (N+1)-th phase becomes 0° is generated on the basis of the operated frequency by a numerical value control oscillator 10 and local signals are generated by sine and cosine generators 13, 14. The outputs of said generators 13, 14 and the input data of the register 7 are operated by multipliers 11, 12, adders 15, 16 and an operator 17 to calculate a phase angle.


Inventors:
SAGAWA KAZUMI
Application Number:
JP11864789A
Publication Date:
December 11, 1990
Filing Date:
May 15, 1989
Export Citation:
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Assignee:
NEC CORP
International Classes:
G01R25/08; H04L27/22; H04L27/227; H04L27/38; (IPC1-7): G01R25/08
Attorney, Agent or Firm:
Tan Ashida (2 outside)