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:
Oct. 02, 1984
Filed:
Dec. 27, 1982
Koichiro Takeda, Abiko, JP;
Tokihiro Miyo, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
In the base-band carrier-recovery circuit used in the demodulator of radio equipment using a PSK modulated signal, a first doubled signal (sin 2.theta.) is obtained by using first and second outputs (sin .theta., cos .theta.) in-phase quadrature with each other from an in-phase quadrature detecting means. A second doubled signal (cos 2.theta.) having a phase difference of 90 degrees from the first doubled signal (sin 2.theta.) is obtained by fullwave rectifying the second output (cos .theta.) and transforming the output waveform. Thereafter a quadrupled signal (sin 4.theta.) is generated from the first and second doubled signals. The quadrupled signal is then fed back to a VCO via a loop filter, thereby recovering the reference carrier signal which is in phase with the received PSK modulated signal.