unconvert.c


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#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 );

    }

}