COMPLEX QUADRATURE MODULATOR, COMPLEX QUADRATURE DEMODULATOR, AND ORTHOGONAL MIXER FOR USE IN BOTH MODULATOR AND DEMODULATOR

摘要

PROBLEM TO BE SOLVED: To provide a realistic complex quadrature modulator, a quadrature demodulator, and an orthogonal mixer circuit applicable to the modulator and the demodulator, having high accuracy to perform digital modulation (and demodulation) to a carrier signal in radio communication etc.;SOLUTION: The complex quadrature modulator/demodulator includes a first and a second orthogonal mixer, to which an in-phase component and an orthogonal component of a baseband signal is input respectively, and generates an orthogonal output from a subtraction result and an addition result relative to the first and second orthogonal mixer outputs. The first and second orthogonal mixers include a first and a second multiplier, respectively. The first multiplier multiplies the in-phase component of the complex baseband signal by the in-phase component and the orthogonal component of a local signal, while the second multiplier multiplies the orthogonal component of the baseband signal by the in-phase component and the orthogonal component of the local signal. Further, the first multiplier and the second multiplier are activated at every 1/4 period of the local signals, and not operated simultaneously.;COPYRIGHT: (C)2012,JPO&INPIT