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:
Apr. 30, 1991
Filed:
Sep. 01, 1989
Yoshinori Hayashi, Shizuoka, JP;
Kenzaburou Iijima, Shizuoka, JP;
Yamaha Corporation, , JP;
Abstract
An absolute encoder for detecting the absolute (as opposed to the relative) rotational displacement of an encoder shaft includes a pair of pitch signals recorded on tracks and an associated signal processing circuit. The pair of pitch signals have different periods (wave lengths) which are such that they have no common factors. The signal processing circuit includes magnetic sensors for producing absolute position data indicative of the degree of displacement of the encoder shaft, on the basis of the pitch signals. Through the use of a pair of pitch signals having periods with no common factor, a high degree of resolution is obtained, without having no significantly increase the number of pitch signal tracks.