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:
May. 02, 1995
Filed:
Mar. 01, 1993
NEC Corporation, Tokyo, JP;
Abstract
A data demodulator wholly consisting of digital circuits for time division multi-access (TDMA) signals subjected to differential phase-shift-keying (DPSK) is provided. The data demodulator generates a phase difference signal by subjecting .pi./4-shift quadrature phase-shift-keying (.pi./4 QPSK) signals to delayed detection of phase in synchronism with N-phase clock signals (where N is a positive integer), and reproduces a resulting phase difference signal into decision data. A first such data demodulator detects decision errors from the phase difference signal and decision data, and achieves symbol synchronism by sampling the decision data in a clock signal phase involving little decision error. A second such data demodulator supplies the phase difference signal after correcting its D.C. offset due to a frequency drift. In these two data demodulators, the formulas for computing said decision errors and correction values are flexibly varied according to preceding burst information.