Title:
METHOD AND CIRCUIT FOR PHASE DIFFERENCE DETECTION, AND ITS DEVICE
Document Type and Number:
Japanese Patent JP2938360
Kind Code:
B2
Abstract:
PURPOSE: To easily and accurately detect the phase difference between light signal and electrical signal by directly calculating the product of a voltage signal and a light signal by a photoconductive type light receiver and detecting the phase difference from a standardized phase difference value based on a time average value and the intensity value of a current signal.
CONSTITUTION: When a light signal enters a photoconductive type light receiver 110 to which a voltage is applied, a current corresponding to the product of a voltage signal and a light signal flows to the light receiver 110. The current signal is inputted to a current-voltage conversion part 120 to be converted into a voltage signal, and then it is outputted. An LPF 131 outputs a DC voltage by inputting the voltage signal and calculating an time average. On the other hand, an RMS-DC conversion circuit 132 converts the RMS voltage of the voltage signal to a DC voltage, thus outputting a value proportional to the signal intensity of the light signal and voltage signal. Therefore by dividing the time average output from the LPF 131 by a value proportional to the signal intensity using a division circuit 133, a standardized phase difference output which does not depend on the intensity of the light signal and voltage signal can be obtained.
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Inventors:
TAKESHIMA AKIRA
NISHIZAWA MITSUAKI
KOISHI JU
NISHIZAWA MITSUAKI
KOISHI JU
Application Number:
JP893695A
Publication Date:
August 23, 1999
Filing Date:
January 24, 1995
Export Citation:
Assignee:
HAMAMATSU HOTONIKUSU KK
International Classes:
G01J9/00; G01J1/44; G01R25/00; (IPC1-7): G01J9/00; G01J1/44
Domestic Patent References:
JP7120327A | ||||
JP712510A | ||||
JP5198829A | ||||
JP63114429A |
Attorney, Agent or Firm:
Yoshiki Hasegawa (3 outside)
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