GNU Radio Manual and C++ API Reference 3.8.5.0
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freq_xlating_fir_filter.h
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1/* -*- c++ -*- */
2/*
3 * Copyright 2002,2004,2012,2018 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 FREQ_XLATING_FIR_FILTER_H
24#define FREQ_XLATING_FIR_FILTER_H
25
26#include <gnuradio/filter/api.h>
28
29namespace gr {
30namespace filter {
31
32
33/*!
34 * \brief FIR filter combined with frequency translation with
35 * IN_T input, OUT_T output and TAP_T taps
36 *
37 * \ingroup channelizers_blk
38 *
39 * This class efficiently combines a frequency translation
40 * (typically "down conversion") with a FIR filter (typically
41 * low-pass) and decimation. It is ideally suited for a "channel
42 * selection filter" and can be efficiently used to select and
43 * decimate a narrow band signal out of wide bandwidth input.
44 *
45 * Uses a single input array to produce a single output array.
46 * Additional inputs and/or outputs are ignored.
47 *
48 * - freq (input):
49 * Receives a PMT pair: (intern("freq"), double(frequency).
50 * The block then sets its frequency translation value to
51 * the new frequency provided by the message. A tag is then
52 * produced when the new frequency is applied to let
53 * downstream blocks know when this has taken affect.
54 * Use the filter's group delay to determine when the
55 * transients after the change have settled down.
56 */
57template <class IN_T, class OUT_T, class TAP_T>
59{
60public:
61 typedef boost::shared_ptr<freq_xlating_fir_filter<IN_T, OUT_T, TAP_T>> sptr;
62
63 /*!
64 * \brief FIR filter with IN_T input, OUT_T output, and
65 * TAP_T taps that also frequency translates a signal from
66 * \p center_freq.
67 *
68 * Construct a FIR filter with the given taps and a composite
69 * frequency translation that shifts center_freq down to zero
70 * Hz. The frequency translation logically comes before the
71 * filtering operation.
72 *
73 * \param decimation set the integer decimation rate
74 * \param taps a vector/list of taps of type TAP_T
75 * \param center_freq Center frequency of signal to down convert from (Hz)
76 * \param sampling_freq Sampling rate of signal (in Hz)
77 */
78 static sptr make(int decimation,
79 const std::vector<TAP_T>& taps,
80 double center_freq,
81 double sampling_freq);
82
83 virtual void set_center_freq(double center_freq) = 0;
84 virtual double center_freq() const = 0;
85
86 virtual void set_taps(const std::vector<TAP_T>& taps) = 0;
87 virtual std::vector<TAP_T> taps() const = 0;
88};
100
101
102} /* namespace filter */
103} /* namespace gr */
104
105#endif /* FREQ_XLATING_FIR_FILTER_H */
FIR filter combined with frequency translation with IN_T input, OUT_T output and TAP_T taps.
Definition freq_xlating_fir_filter.h:59
virtual void set_taps(const std::vector< TAP_T > &taps)=0
virtual std::vector< TAP_T > taps() const =0
static sptr make(int decimation, const std::vector< TAP_T > &taps, double center_freq, double sampling_freq)
FIR filter with IN_T input, OUT_T output, and TAP_T taps that also frequency translates a signal from...
virtual double center_freq() const =0
virtual void set_center_freq(double center_freq)=0
boost::shared_ptr< freq_xlating_fir_filter< IN_T, OUT_T, TAP_T > > sptr
Definition freq_xlating_fir_filter.h:61
synchronous N:1 input to output with history
Definition sync_decimator.h:38
#define FILTER_API
Definition gr-filter/include/gnuradio/filter/api.h:30
static const float taps[NSTEPS+1][NTAPS]
Definition interpolator_taps.h:9
freq_xlating_fir_filter< gr_complex, gr_complex, gr_complex > freq_xlating_fir_filter_ccc
Definition freq_xlating_fir_filter.h:90
freq_xlating_fir_filter< gr_complex, gr_complex, float > freq_xlating_fir_filter_ccf
Definition freq_xlating_fir_filter.h:92
freq_xlating_fir_filter< std::int16_t, gr_complex, float > freq_xlating_fir_filter_scf
Definition freq_xlating_fir_filter.h:97
freq_xlating_fir_filter< std::int16_t, gr_complex, gr_complex > freq_xlating_fir_filter_scc
Definition freq_xlating_fir_filter.h:99
freq_xlating_fir_filter< float, gr_complex, float > freq_xlating_fir_filter_fcf
Definition freq_xlating_fir_filter.h:95
freq_xlating_fir_filter< float, gr_complex, gr_complex > freq_xlating_fir_filter_fcc
Definition freq_xlating_fir_filter.h:94
GNU Radio logging wrapper for log4cpp library (C++ port of log4j)
Definition basic_block.h:46