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1. 发明专利

AU3384193A DATA DEMODULATOR 未知
公开(公告)号：AU3384193A
公开(公告)日：1993-09-02
申请号：AU3384193
申请日：1993-02-26
申请人： NEC CORPORATION
发明人： TOSHIFUMI SATO , TAKAYUKI SHIBATA , HIDEO OHMURA
IPC分类号： H04L27/233
摘要： A data demodulator wholly consisting of digital circuits for TDMA signals subjected to differential phase-shift-keying (DPSK). The data demodulator generates a phase difference signal by subjecting pi /4QPSK signals to delayed detection with phase detection means, delay means and phase difference detection means, connected in cascade and all known to persons skilled in the art, in synchronism with N-phase clock signals, and reproduces this phase difference signal into decision data with definition means. A first such data demodulator finds out decision errors from said phase difference signal and decision data, and achieves symbol synchronism by sampling said decision data in a clock signal phase involving little decision error. A second such data demodulator supplies said phase difference signal to said decision 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.

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