Title:
PHASE DETECTOR
Document Type and Number:
Japanese Patent JP3048467
Kind Code:
B2
Abstract:
PURPOSE: To detect the phase difference between two AC Inputs speedily and accurately with an inexpensive configuration by sampling first and second AC input values at each specified sampling frequency.
CONSTITUTION: A sampling means 41 samples the digital value of AC inputs A1 and A2 at each specified frequency fs. Then, the means 41 outputs continuous sampling values X10 and X11 for the input A1 and continuous sampling values X20 and X21 for an input A2 to a polarity change detection means 42 and a phase difference detection means 43. Then, after calculating each absolute value sum (&verbar X1&verbar and &verbar X2&verbar ) of sampling values (X10, X11) and (X20, X21) by an equation I in the case of input to a polarity change detection signal, a sampling value (X'20, X'21) where the sampling value (X20, X21) of a second AC input is normalized according to the ratio (&verbar X1&verbar /&verbar X2&verbar ) of the absolute value sums is calculated by an equation II and then a phase difference θ between first and second AC inputs is calculated by an equation III. An allowable difference discrimination means 44 compares the phase difference θ with a setting value θs and then judges that the difference is within an allowable difference in the case of θ≤θs, thus outputting the phase difference θ to 2 digital output device 5.
Inventors:
Hiroshi Igawa
Application Number:
JP15832192A
Publication Date:
June 05, 2000
Filing Date:
June 17, 1992
Export Citation:
Assignee:
Toshiba Corporation
International Classes:
G01R25/00; (IPC1-7): G01R25/00
Domestic Patent References:
| JP5037473A | ||||
| JP5942460A | ||||
| JP6466566A | ||||
| JP4942713B1 |
Attorney, Agent or Firm:
Kazuo Sato (3 others)