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. 05, 1994
Filed:
Aug. 31, 1992
Patrick Vandamme, Perros Guirec, FR;
Joelle Kervarec, Pleumeur Bodou, FR;
Alain Leclert, Ploulec'h, FR;
France Telecom, , FR;
Abstract
A coherent demodulating device is characterized by a demodulating circuit and a carrier recovering circuit produced entirely in digital form. Two quadrature demodulation carrier waves produced by a local oscillator are mixed with a demodulation carrier signal modulated by symbols to produce analog signals. The analog signals are digitized by sampling at symbol reception frequency into incoming digital signals. A digital phase shifter phase shifts the incoming signals by a demodulation phase derived by a phase loop digital processing circuit as from error signal pulses supplied by a comparing circuit receiving outgoing digital signals from the phase shifter. The compensation for the phase and frequency differences between the demodulation and modulation carrier waves is carried out a posteriori in digital form by phase shifting the incoming signals.