Allan R Hambley

US Patent:

47150475, Dec 22, 1987

Filed:

Apr 4, 1986

Appl. No.:

6/848063

Inventors:

Allan R. Hambley - Atlantic Mine MI

Assignee:

Harris Corporation - Melbourne FL

International Classification:

H04L 2722

US Classification:

375 84

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.

Author:

Allan R. Hambley

ISBN #:

0023493313

Author:

Allan R. Hambley

ISBN #:

0130329711

Author:

Allan R. Hambley

ISBN #:

0130610704

Author:

Allan R. Hambley

ISBN #:

0136919820

Author:

Allan R. Hambley

ISBN #:

0716781840

Author:

Allan R. Hambley

ISBN #:

8420529990