Quadrature modulator / demodulator, quadrature modulator and quadrature demodulator

摘要

PPROBLEM TO BE SOLVED: To reduce the effect of error, in the signal subjected to quadrature demodulation, attributable to a quadrature modulator. PSOLUTION: The quadrature modulator 2 includes: a modulation local signal source 22 for outputting a modulation local signal; a first modulation multiplier 21I which multiplies the modulation local signal and a test I signal; a second modulation multiplier 21Q which multiplies the modulation quadrature local signal whose phase is orthogonal to the modulation local signal and a test Q signal; and an adder 25 which adds the outputs of the first modulation multiplier 21I and second modulation multiplier 21Q. A quadrature demodulator 4 includes: a demodulation local signal source 42 for outputting a demodulation local signal; a first demodulation multiplier 41I which multiplies the demodulation local signal with an output of the adder 25; and a second demodulation multiplier 41Q which multiplies the demodulation quadrature local signal whose phase is orthogonal to the demodulation local signal and the output of the adder 25. Here, a frequency fSBLO1/SBof the modulation local signal is different from a frequency fSBLO2/SBof the demodulation local signal. PCOPYRIGHT: (C)2009,JPO&INPIT