| 摘要 |
PURPOSE: A digital filter is provided to improve the operation efficiency by reconstructing the digital filter according to input signals. CONSTITUTION: An I-channel delayer group(410) comprising several delayers(D1,D2,...,DZ) in series synchronizes I-channel's QAM(quadrature amplitude modulation)-modulated symbol data with symbol clock of period T and shifts them successively. A Q-channel delayer group(420) comprising several delayers(D1,D2,...D,Z) in series corresponding to each delayer of the I-channel delayer group(410) synchronizes Q-channel's QAM-modulated symbol data with the symbol clock of period T and shifts them successively. A first multiplexer group(430) comprises a first multiplexer(M0) and several multiplexers(M1,M2,...,Mz) corresponding to each delayer of the Q-channel delayer group(420). A second multiplexer group(440) comprising several multiplexers(M1,M2,...,Mz) corresponding to each delayer of the I-channel delayer group(410) outputs different filter coefficients. A multiplier group(450) multiplies the multiplexer output of the second multiplexer group(440). An adder(460) sums up all the outputs of each multiplier of the multiplier group(450). A second multiplexer(470) selects from 1 and -1 alternatively with a period of 2T/n. A multiplier(480) multiplies the output of the adder(460) and the second multiplexer(470).
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