sdrangel/sdrbase/dsp/fftfilt.h

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1.5 KiB
C
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/*
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* Filters from Fldigi.
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*/
#ifndef _FFTFILT_H
#define _FFTFILT_H
#include <complex>
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#include "gfft.h"
//----------------------------------------------------------------------
class fftfilt {
enum {NONE, BLACKMAN, HAMMING, HANNING};
public:
typedef std::complex<float> cmplx;
fftfilt(float f1, float f2, int len);
fftfilt(float f2, int len);
~fftfilt();
// f1 < f2 ==> bandpass
// f1 > f2 ==> band reject
void create_filter(float f1, float f2);
void create_dsb_filter(float f2);
int noFilt(const cmplx& in, cmplx **out);
int runFilt(const cmplx& in, cmplx **out);
int runSSB(const cmplx& in, cmplx **out, bool usb);
int runDSB(const cmplx& in, cmplx **out);
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protected:
int flen;
int flen2;
g_fft<float> *fft;
g_fft<float> *ift;
cmplx *filter;
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cmplx *data;
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cmplx *ovlbuf;
cmplx *output;
int inptr;
int pass;
int window;
inline float fsinc(float fc, int i, int len) {
return (i == len/2) ? 2.0 * fc:
sin(2 * M_PI * fc * (i - len/2)) / (M_PI * (i - len/2));
}
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inline float _blackman(int i, int len) {
return (0.42 -
0.50 * cos(2.0 * M_PI * i / len) +
0.08 * cos(4.0 * M_PI * i / len));
}
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void init_filter();
void init_dsb_filter();
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};
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/* Sliding FFT filter from Fldigi */
class sfft {
#define K1 0.99999
public:
typedef std::complex<float> cmplx;
sfft(int len);
~sfft();
void run(const cmplx& input);
void fetch(float *result);
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private:
int fftlen;
int first;
int last;
int ptr;
struct vrot_bins_pair;
vrot_bins_pair *vrot_bins;
cmplx *delay;
float k2;
};
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#endif