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:
Feb. 28, 1989
Filed:
Feb. 11, 1987
Applicant:
Inventors:
Sumio Kobayashi, Funabashi, JP;
Mutsuo Tokashiki, Narashino, JP;
Hiroyuki Tomita, Funabashi, JP;
Tadashi Okawa, Funabashi, JP;
Hiroshi Sugai, Sakura, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01P / ; G01P / ;
U.S. Cl.
CPC ...
324163 ; 324166 ; 324161 ;
Abstract
A signal whose frequency is proportional to a rotational speed of a rotor and whose rising and falling angles near points crossing zero becomes larger with the rotational speed of the rotor is used to produce a first signal of amplitude corresponding to the rising and falling angles and a second signal of amplitude corresponding to the frequency, a difference between the first and second signals is evaluated, and the first or second signals are corrected with the difference.