1 // ----------------------------------------------------------------------------
2 // Copyright (C) 2014
3 //              David Freese, W1HKJ
4 //
5 // This file is part of fldigi
6 //
7 // fldigi is free software; you can redistribute it and/or modify
8 // it under the terms of the GNU General Public License as published by
9 // the Free Software Foundation; either version 3 of the License, or
10 // (at your option) any later version.
11 //
12 // fldigi is distributed in the hope that it will be useful,
13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 // GNU General Public License for more details.
16 //
17 // You should have received a copy of the GNU General Public License
18 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
19 // ----------------------------------------------------------------------------
20 
21 #ifndef	_FFTFILT_H
22 #define	_FFTFILT_H
23 
24 #include "complex.h"
25 #include "gfft.h"
26 
27 //----------------------------------------------------------------------
28 
29 class fftfilt {
30 enum {NONE, BLACKMAN, HAMMING, HANNING};
31 
32 protected:
33 	int flen;
34 	int flen2;
35 	g_fft<double> *fft;
36 	g_fft<double> *ift;
37 	cmplx *ht;
38 	cmplx *filter;
39 	cmplx *timedata;
40 	cmplx *freqdata;
41 	cmplx *ovlbuf;
42 	cmplx *output;
43 	int inptr;
44 	int pass;
45 	int window;
46 
fsinc(double fc,int i,int len)47 	inline double fsinc(double fc, int i, int len) {
48 		return (i == len/2) ? 2.0 * fc:
49 				sin(2 * M_PI * fc * (i - len/2)) / (M_PI * (i - len/2));
50 	}
_blackman(int i,int len)51 	inline double _blackman(int i, int len) {
52 		return (0.42 -
53 				 0.50 * cos(2.0 * M_PI * i / len) +
54 				 0.08 * cos(4.0 * M_PI * i / len));
55 	}
56 	void init_filter();
57 	void clear_filter();
58 
59 public:
60 	fftfilt(double f1, double f2, int len);
61 	fftfilt(double f, int len);
62 	~fftfilt();
63 // f1 < f2 ==> bandpass
64 // f1 > f2 ==> band reject
65 	void create_filter(double f1, double f2);
create_lpf(double f)66 	void create_lpf(double f) {
67 		create_filter(0, f);
68 	}
create_hpf(double f)69 	void create_hpf(double f) {
70 		create_filter(f, 0);
71 	}
72 	void rtty_filter(double);
73 
74 	int run(const cmplx& in, cmplx **out);
75 	int flush_size();
76 };
77 
78 #endif
79