#include "fftease.h" void unconvert( float *C, float *S, int N2, float *lastphase, float fundamental, float factor ) { int i, real, imag, amp, freq; float mag, phase; double sin(), cos(); for ( i = 0; i <= N2; i++ ) { imag = freq = ( real = amp = i<<1 ) + 1; if ( i == N2 ) real = 1; mag = C[amp]; lastphase[i] += C[freq] - i*fundamental; phase = lastphase[i]*factor; S[real] = mag*cos( phase ); if ( i != N2 ) S[imag] = -mag*sin( phase ); } }