GNU Radio C++ API Reference: fft_v.h Source File

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fft_v.h
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1/* -*- c++ -*- */
2/*
3 * Copyright 2004,2007,2008,2012,2018,2020 Free Software Foundation, Inc.
4 *
5 * This file is part of GNU Radio
6 *
7 * SPDX-License-Identifier: GPL-3.0-or-later
8 *
9 */
10
11#ifndef INCLUDED_FFT_FFT_V_H
12#define INCLUDED_FFT_FFT_V_H
13
14#include <gnuradio/fft/api.h>
15#include <gnuradio/sync_block.h>
16
17namespace gr {
18namespace fft {
19
20/*!
21 * \brief Compute forward or reverse FFT. complex vector in / complex vector out.
22 * \ingroup fourier_analysis_blk
23 *
24 * The FFT operation is defined for a vector \f$x\f$ with \f$N\f$ uniformly
25 * sampled points by
26 *
27 * \f[ X(a) = \sum_{k=0}^{N-1} x(a) \cdot e^{-j 2\pi k a / N} \f]
28 *
29 * \f$ X = FFT\{x\} \f$ is the the FFT transform of \f$x(a)\f$, \f$j\f$ is
30 * the imaginary unit, \f$k\f$ and \f$a\f$ range from \f$0\f$ to \f$N-1\f$.
31 *
32 * The IFFT operation is defined for a vector \f$y\f$ with \f$N\f$
33 * uniformly sampled points by
34 *
35 * \f[ Y(b) = \sum_{k=0}^{N-1} y(b) \cdot e^{j 2\pi k b / N} \f]
36 *
37 * \f$Y = IFFT\{y\}\f$ is the the inverse FFT transform of \f$y(b)\f$,
38 * \f$j\f$ is the imaginary unit, \f$k\f$ and \f$b\f$ range from \f$0\f$ to
39 * \f$N-1\f$.
40 *
41 * \b Note, that due to the underlying FFTW library, the output of a FFT
42 * followed by an IFFT (or the other way around) will be scaled i.e.
43 * \f$FFT\{ \, IFFT\{x\} \,\} = N \cdot x \neq x\f$.
44 *
45 * \see http://www.fftw.org/faq/section3.html#whyscaled
46 */
47template <class T, bool forward>
48 class FFT_API fft_v : virtual public sync_block
49{
50public:
51 typedef std::shared_ptr<fft_v<T, forward>> sptr;
52 /*! \brief
53 * \param[in] fft_size N.
54 * \param[in] window Window function to be used.
55 * \param[in] shift True moves DC carrier to the middle.
56 * \param[in] nthreads Number of underlying threads.
57 */
58 static sptr make(int fft_size,
59 const std::vector<float>& window,
60 bool shift = false,
61 int nthreads = 1);
62
63 virtual void set_nthreads(int n) = 0;
64
65 virtual int nthreads() const = 0;
66
67 virtual bool set_window(const std::vector<float>& window) = 0;
68};
69
70} /* namespace fft */
71} /* namespace gr */
72
73#endif /* INCLUDED_FFT_FFT_V_H */
gr::fft::fft_v
Compute forward or reverse FFT. complex vector in / complex vector out.
Definition fft_v.h:49
gr::fft::fft_v::sptr
std::shared_ptr< fft_v< T, forward > > sptr
Definition fft_v.h:51
gr::fft::fft_v::set_nthreads
virtual void set_nthreads(int n)=0
gr::fft::fft_v::set_window
virtual bool set_window(const std::vector< float > &window)=0
gr::fft::fft_v::make
static sptr make(int fft_size, const std::vector< float > &window, bool shift=false, int nthreads=1)
gr::fft::fft_v::nthreads
virtual int nthreads() const =0
gr::fft::window
Definition window.h:23
gr::sync_block::sync_block
sync_block(void)
Definition sync_block.h:28
api.h
FFT_API
#define FFT_API
Definition gr-fft/include/gnuradio/fft/api.h:18
gr::fft
Definition ctrlport_probe_psd.h:18
gr
GNU Radio logging wrapper.
Definition basic_block.h:29
sync_block.h