FFT快速傅里也变换

fft程序，DimREX(512)'REX[]holdstherealpartofthefrequencydomainDimIMX(512)'IMX[]holdstheimaginarypartofthefrequencydomainConstN=512PublicSubfft()pi=3.14159265'Setconstants1000'THEFASTFOURIERTRANSFORM'copyright©1997-1999byCaliforniaTechnicalPublishing'publ