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. 11, 1986
Filed:
Apr. 19, 1983
Applicant:
Inventors:
Yoshikazu Nishiwaki, Osaka, JP;
Yozo Nishiura, Osaka, JP;
Assignee:
Sumitomo Electric Industries Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01P / ;
U.S. Cl.
CPC ...
356 285 ; 356346 ; 356349 ; 343 / ;
Abstract
A method and apparatus for detecting a frequency change of a light modulates the scattered light from the object of measurement using an acousto-optic modulator or the like, heterodyne-detects the scattered light after modulation to provide an electrical signal having a frequency (f.sub.d -f.sub.m) which is the difference between the Doppler frequency f.sub.d and the modulation frequency f.sub.m, passes this electrical signal to a filter while changing the modulation frequency f.sub.m, and obtains the modulation frequency f.sub.m at which the signal voltage is the largest or the smallest, that is, the Doppler frequency f.sub.d.