First commit

fix_fft.h

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+#ifndef FIXFFT_H
+#define FIXFFT_H
+
+//#include <WProgram.h>  //depreacted included in arduino.h
+
+
+
+
+/*
+  fix_fft() - perform forward/inverse fast Fourier transform.
+  fr[n],fi[n] are real and imaginary arrays, both INPUT AND
+  RESULT (in-place FFT), with 0 <= n < 2**m; set inverse to
+  0 for forward transform (FFT), or 1 for iFFT.
+*/
+int fix_fft(char fr[], char fi[], int m, int inverse);
+
+
+
+/*
+  fix_fftr() - forward/inverse FFT on array of real numbers.
+  Real FFT/iFFT using half-size complex FFT by distributing
+  even/odd samples into real/imaginary arrays respectively.
+  In order to save data space (i.e. to avoid two arrays, one
+  for real, one for imaginary samples), we proceed in the
+  following two steps: a) samples are rearranged in the real
+  array so that all even samples are in places 0-(N/2-1) and
+  all imaginary samples in places (N/2)-(N-1), and b) fix_fft
+  is called with fr and fi pointing to index 0 and index N/2
+  respectively in the original array. The above guarantees
+  that fix_fft "sees" consecutive real samples as alternating
+  real and imaginary samples in the complex array.
+*/
+int fix_fftr(char f[], int m, int inverse);
+static inline char FIX_MPY(char a,char b);
+
+
+
+#endif