amp;pi;/4 SHIFT QPSK MODULATOR AND COMMUNICATION APPARATUS

摘要

PROBLEM TO BE SOLVED: To reduce the storage capacity of ROM for previously storing impulse response data, save power consumption and also reduce a circuit scale. ;SOLUTION: In an impulse response storage part 124 in an impulse response arithmetic circuit 12, the storage capacity of impulse response data is reduced by half by commonly using impulse response data with a waveform at one side in an impulse response waveform being horizontally symmetric with a maximum value as a center. Besides, a read address signal is changed over by an address inverting part 123 with a simple configuration in order not to simultaneously perform access to blocks with two kinds of sizes '1' and '1/2' in the impulse response storage part 124. Besides, an encoding inversion processing and a zero replacement processing corresponding to two pieces of phase information from a shift register 12 are executed by one numerical value converting part 126.;COPYRIGHT: (C)2000,JPO