GNU Radio 3.7.2git-29-g7516b6dd C++ API
fft_filter.h
Go to the documentation of this file.
1 /* -*- c++ -*- */
2 /*
3  * Copyright 2010,2012 Free Software Foundation, Inc.
4  *
5  * This file is part of GNU Radio
6  *
7  * GNU Radio 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, or (at your option)
10  * any later version.
11  *
12  * GNU Radio 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 GNU Radio; see the file COPYING. If not, write to
19  * the Free Software Foundation, Inc., 51 Franklin Street,
20  * Boston, MA 02110-1301, USA.
21  */
22 
23 #ifndef INCLUDED_FILTER_FFT_FILTER_H
24 #define INCLUDED_FILTER_FFT_FILTER_H
25 
26 #include <gnuradio/filter/api.h>
27 #include <vector>
28 #include <gnuradio/gr_complex.h>
29 #include <gnuradio/fft/fft.h>
30 
31 namespace gr {
32  namespace filter {
33  namespace kernel {
34 
35  /*!
36  * \brief Fast FFT filter with float input, float output and float taps
37  * \ingroup filter_blk
38  */
40  {
41  private:
42  int d_ntaps;
43  int d_nsamples;
44  int d_fftsize; // fftsize = ntaps + nsamples - 1
45  int d_decimation;
46  fft::fft_real_fwd *d_fwdfft; // forward "plan"
47  fft::fft_real_rev *d_invfft; // inverse "plan"
48  int d_nthreads; // number of FFTW threads to use
49  std::vector<float> d_tail; // state carried between blocks for overlap-add
50  std::vector<float> d_new_taps;
51  gr_complex *d_xformed_taps; // Fourier xformed taps
52 
53  void compute_sizes(int ntaps);
54  int tailsize() const { return d_ntaps - 1; }
55 
56  public:
57  /*!
58  * \brief Construct an FFT filter for float vectors with the given taps and decimation rate.
59  *
60  * This is the basic implementation for performing FFT filter for fast convolution
61  * in other blocks for complex vectors (such as fft_filter_ccc).
62  *
63  * \param decimation The decimation rate of the filter (int)
64  * \param taps The filter taps (complex)
65  * \param nthreads The number of threads for the FFT to use (int)
66  */
67  fft_filter_fff(int decimation,
68  const std::vector<float> &taps,
69  int nthreads=1);
70 
71  ~fft_filter_fff();
72 
73  /*!
74  * \brief Set new taps for the filter.
75  *
76  * Sets new taps and resets the class properties to handle different sizes
77  * \param taps The filter taps (complex)
78  */
79  int set_taps(const std::vector<float> &taps);
80 
81  /*!
82  * \brief Set number of threads to use.
83  */
84  void set_nthreads(int n);
85 
86  /*!
87  * \brief Get number of threads being used.
88  */
89  int nthreads() const;
90 
91  /*!
92  * \brief Perform the filter operation
93  *
94  * \param nitems The number of items to produce
95  * \param input The input vector to be filtered
96  * \param output The result of the filter operation
97  */
98  int filter(int nitems, const float *input, float *output);
99  };
100 
101 
102  /*!
103  * \brief Fast FFT filter with gr_complex input, gr_complex output and gr_complex taps
104  * \ingroup filter_blk
105  */
107  {
108  private:
109  int d_ntaps;
110  int d_nsamples;
111  int d_fftsize; // fftsize = ntaps + nsamples - 1
112  int d_decimation;
113  fft::fft_complex *d_fwdfft; // forward "plan"
114  fft::fft_complex *d_invfft; // inverse "plan"
115  int d_nthreads; // number of FFTW threads to use
116  std::vector<gr_complex> d_tail; // state carried between blocks for overlap-add
117  std::vector<gr_complex> d_new_taps;
118  gr_complex *d_xformed_taps; // Fourier xformed taps
119 
120  void compute_sizes(int ntaps);
121  int tailsize() const { return d_ntaps - 1; }
122 
123  public:
124  /*!
125  * \brief Construct an FFT filter for complex vectors with the given taps and decimation rate.
126  *
127  * This is the basic implementation for performing FFT filter for fast convolution
128  * in other blocks for complex vectors (such as fft_filter_ccc).
129  *
130  * \param decimation The decimation rate of the filter (int)
131  * \param taps The filter taps (complex)
132  * \param nthreads The number of threads for the FFT to use (int)
133  */
134  fft_filter_ccc(int decimation,
135  const std::vector<gr_complex> &taps,
136  int nthreads=1);
137 
138  ~fft_filter_ccc();
139 
140  /*!
141  * \brief Set new taps for the filter.
142  *
143  * Sets new taps and resets the class properties to handle different sizes
144  * \param taps The filter taps (complex)
145  */
146  int set_taps(const std::vector<gr_complex> &taps);
147 
148  /*!
149  * \brief Set number of threads to use.
150  */
151  void set_nthreads(int n);
152 
153  /*!
154  * \brief Get number of threads being used.
155  */
156  int nthreads() const;
157 
158  /*!
159  * \brief Perform the filter operation
160  *
161  * \param nitems The number of items to produce
162  * \param input The input vector to be filtered
163  * \param output The result of the filter operation
164  */
165  int filter(int nitems, const gr_complex *input, gr_complex *output);
166  };
167 
168  } /* namespace kernel */
169  } /* namespace filter */
170 } /* namespace gr */
171 
172 #endif /* INCLUDED_FILTER_FFT_FILTER_H */