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:
Nov. 01, 1988
Filed:
Jun. 16, 1987
Tomomitsu Kuroyanagi, Katsuta, JP;
Yukinari Ueki, Yokohama, JP;
Shuzo Matsumoto, Fujisawa, JP;
Masanori Kamiya, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A phase shift circuit comprises a variable phase shifter responsive to an externally supplied voltage to change the amount of phase shift, and a phase detector operative to detect a phase difference between input and output signals of the variable phase shifter and supply a voltage complying with the phase difference to the variable phase shifter. When the center frequency of the variable phase shifter is changed by reason of production errors and temperature variations to deviate the phase shift amount from a desired value, the phase detector controls the center frequency such that the phase shift amount can be fixed to the desirably predetermined value.