Patent ID: 6683921
Filing Date: 2004-01-27
Classification: H04L

Abstract:
An apparatus for generating an absolute phase of a signal received by a receiver, said receiver comprising demodulating means for demodulating a signal to be PSK-modulated in which at least an 8PSK-modulated digital signal among an 8PSK-modulated digital signal, a QPSK-modulated digital signal, and a BPSK-modulated digital signal is time-multiplexed with a BPSK-modulated frame-synchronizing signal, by using carrier waves (fc1 and fc2) regenerated by carrier-wave regenerating means and outputting I and Q symbol-stream data (I(8) and Q(8)); frame-synchronizing-signal acquiring means (2) for acquiring a frame-synchronizing signal from the demodulated I and Q symbol-stream data; received-signal-phase rotation angle detecting means for detecting a phase rotation angle (R(3)) of I and Q symbol-stream data output from the demodulating means against the transmission side; and antiphase rotating means (7) for antiphase-rotating a phase of I and Q symbol-stream data output from the demodulating means by a phase rotation angle (R(3)) detected by the received-signal-phase rotation angle detecting means so that the carrier-wave regenerating means of the demodulating means has phase error tables (13, 14-1, and 15-1 to 15-4) storing carrier-wave phase error data (&Dgr;&phgr;(8)) for various demodulated I and Q symbol-stream data sets for each modulation system, reads phase error data corresponding to the demodulated I and Q symbol-stream data from a phase error table of a corresponding modulation system while the demodulating means demodulates a certain modulation-system portion upon normal reception, and corrects a phase of a carrier wave; wherein said apparatus is characterized in thatsaid received-signal phase-rotation-angle detecting means (8A, 8B, 8C, or 8D) include phase-error-data reading means (16A, 16B, 16C, and 16D) for reading high-order bits (&Dgr;&phgr;(3) and (&Dgr;&phgr;â€²(3)) for judging whether the absolute value of a phase error is larger or smaller than (&pgr;/8)+sÂ·(&pgr;/4) (s is 0 or 1) or &pgr;/8 among phase error data corresponding to the demodulated I and Q symbol-stream data from a phase error table (15-1 to 15-4 or 14-1, 14-2) for BPSK modulation of the carrier-wave regenerating means (10A, 10B, 10C or 10D) and discriminating means (92 or 92B) for discriminating a phase rotation angle of a symbol portion corresponding to bit (0) (or bit (1)) of a frame-synchronizing signal against the transmission side in I and Q symbol-stream data output from demodulating means (1A, 1B, 1C, 1D, 1E, or 1F) in accordance with the sign bit data (i(1) and iâ€²(1)) of I (or Q) symbol-stream data of a portion corresponding to bit (0) (or bit (1)) of a frame-synchronizing signal acquired by the frame-synchronizing-signal acquiring means in demodulated I and Q symbol-stream data (I(8) or Q(8)) and phase error data (&Dgr;&phgr;(8) or (&Dgr;&phgr;â€²(8)) read by the phase error data reading means correspondingly to the portion and outputting a discrimination result (R(3)).