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. 22, 1987
Filed:
Apr. 04, 1986
Allan R Hambley, Atlantic Mine, MI (US);
Harris Corporation, Melbourne, FL (US);
Abstract
A differential phase shift keyed demodulator for demodulating a differential phase shift key modulated signal and synchronizing the clock thereof. To accomplish the demodulation, the differential phase shift keyed modulated signal is mixed with three reference signals offset by 120.degree.. This process creates three threshold boundaries in the XY vector phase plane and the three mixed signals are logically related to determine in which sector the instantaneous phase lies. The instantaneous phase at a first time is delayed for comparison with the instantaneous phase at a successive time. The result of this comparison process produces a signal representing the information. Synchronization of the data clock is accomplished by comparing the phase of the signal resulting from the demodulation at points midway between data decisions. The resulting signal from this comparison process controls a voltage-controlled oscillator such that when the clock is early the frequency of the voltage-controlled oscillator tends to increase, and when the clock is late the frequency of the voltage-controlled oscillator tends to decrease.