The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 24, 1999
Filed:
Oct. 19, 1995
Takashi Tanaka, Tokyo, JP;
Masaaki Kusumi, Tokyo, JP;
Sony Magnescale Inc., Tokyo, JP;
Abstract
A displacement detecting apparatus includes an error correcting circuit through which a pair of sine wave signals detected by a detecting head unit are corrected. A signal detecting circuit receives the pair of sine wave signals whose phases are shifted by about 90.degree., and detects a magnitude of one of the two sine wave signal when the other one of the two sine wave signals crosses with a reference voltage level. The error correcting circuit calculates an error correction amount of each sine wave signal according to the detected magnitude of the signal and eliminates the calculated error correction amount from the signals. Therefore, the sine wave signals of position information are accurately corrected in direct-current component, voltage ratio and phase difference.