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. 25, 2000
Filed:
Jun. 25, 1998
Hisaya Ishihara, Kanagawa, JP;
NEC Corporation, Tokyo, JP;
Abstract
A phase shift circuit includes a CR phase shifter for receiving an input signal to output a pair of first signals having a 90.degree. phase difference therebetween, a pair of variable-gain amplifiers for receiving the first signals to output a pair of second signals, an adder for adding both the second signals to output a sum signal, a subtracter for outputting a difference signal between the second signals, and a phase error detector for detecting the phase difference between the outputs from the adder and the subtracter to output a pair of gain control signal based on the phase difference. The gain control signal is fed-back to the variable-gain amplifier to control the ratio between the gains of the variable-gain amplifiers.