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. 01, 1983
Filed:
Apr. 03, 1980
Michael D Rubin, Saratoga, CA (US);
Ford Aerospace & Communications Corporation, Detroit, MI (US);
Abstract
A differentially coherent signal detector capable of detecting arbitrary-even-ordered phase shift keyed signals, such as quadraphase (QSK), hex (HSK), octo (OSK), etc. In the case of QSK, the signal to be demodulated is split. One portion is delayed while the other portion is fed to a variable phase shifter and then to a hybrid splitter. The delayed signal and quadrature output of the hybrid splitter are fed to a quadraphase detector which recovers the information. The delayed signal and inphase output of the hybrid splitter are each fed to a phase tracking circuit via frequency doublers. The phase tracker controls the variable phase shifter in a manner which maximizes the detected signal by compensating for phase variations introduced by the delay element. In the case of Nth-order phase shift keyed signals, where N is even, the frequency doublers are replaced by frequency multipliers having a multiplication factor of N/2, and the quadraphase detector is replaced by a detector capable of detecting that particular order.