INVERSE FOURIER TRANSFORM CIRCUIT AND INVERSE FOURIER TRANSFORM METHOD

摘要

PROBLEM TO BE SOLVED: To provide an inverse Fourier transform circuit necessitating a less amount of arithmetic calculation and to provide an inverse Fourier transform method. SOLUTION: Polarity inverters 101-104 invert the polarity of the cosine wave of each subcarrier. Changeover switches 111-114 are used to provide an output of the cosine wave of each subcarrier when the value of the in-phase component of each base band signal is '+1' or to provide an output of the polarity inversed value of the cosine wave of each subcarrier when the value of the in- phase component of each band signal is '-1'. Polarity inverters 105-108 invert the polarity of the sine wave of each subcarrier. Changeover switches 115-118 are used to provide an output of the sine wave of each subcarrier when the value of an orthogonal component of each base band signal is '+1' or to provide an output of the polarity inversed value of the sine wave of each subcarrier when the value of the orthogonal component of each base band signal is '-1'.