CDMA DEMODULATION CIRCUIT

摘要

PURPOSE: To shorten the convergence time of the tap coefficient of an adaptive control orthogonalizing filter used in the demodulation circuit used for demodulation in a radio reception part in the CDMA system. CONSTITUTION: The output of a phase error compensation part 107 is outputted with a pilot symbol period and is held for a time of several symbols by a timing adjusting function part 110. An error generation circuit 109 uses the held phase compensation value to generate an error vector for each information symbol in accordance with the signal vector after discrimination and decision and that before the discrimination and decision. The error vector is successively inputted to a tap coefficient control part 111 with the symbol period. This part 111 updates the tap coefficient of the orthogonalizing filter with the symbol period. Since the value of the tap coefficient can be quickly converged to an optimum value, the time when the service quality is degraded is shortened even if the state of an interference wave is changed by call originating or terminating of another user on the way of service.