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:
Dec. 10, 1991
Filed:
Jun. 18, 1990
Applicant:
Inventors:
Steven H Pepper, Portland, OR (US);
Jeffrey H Goll, Lake Oswego, OR (US);
Assignee:
Tektronix, Inc., Beaverton, OR (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03K / ;
U.S. Cl.
CPC ...
307510 ; 307491 ; 328161 ;
Abstract
An automatic gain control circuit for an interferometer or a phase sensitive detector reduces sensitivity to fluctuations in amplitude of input signals. A pair of currents from the phase sensitive detector that represents a detected phase difference are input to an automatic gain control ratio detector. The output of the automatic gain control ratio detector is a function of the ratio of the difference and sum of the phase sensitive detector currents that is substantially independent of intensity or amplitude fluctuations of the input signals.