GNU Radio Manual and C++ API Reference  3.7.11
The Free & Open Software Radio Ecosystem
test_tag_variable_rate_ff.h
Go to the documentation of this file.
1 /* -*- c++ -*- */
2 /*
3  * Copyright 2015 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_GR_TEST_TAG_VARIABLE_RATE_FF_H
24 #define INCLUDED_GR_TEST_TAG_VARIABLE_RATE_FF_H
25 
26 #include <gnuradio/blocks/api.h>
27 #include <gnuradio/block.h>
28 
29 namespace gr {
30  namespace blocks {
31 
32  /*!
33  * \brief Used for testing tag propagation.
34  * \ingroup measurement_tools_blk
35  * \ingroup stream_tag_tools_blk
36  * \ingroup debug_tools_blk
37  *
38  * This block resamples the stream by a factor that starts at 0.5
39  * but varies around by some random walk. The relative rate of the
40  * block is initialized to 0.5 and the random number generator is
41  * seeded based on the time. For each input, if the random number
42  * is >= 0.5, the relative rate is increased by \p update_step;
43  * otherwise, it is decreased by \p update_step.
44  *
45  * The rate of the change of the resampling factor is set by the
46  * flag \p update_once. If this is set to true, then the rate is
47  * only updated once per work function. If it is set to false
48  * (default), then the rate is changed with every input sample.
49  *
50  * The block's ctor sets the propagation policy to TPP_DONT to
51  * stop tags from automatically propagating. Instead, we handle
52  * the tag propagation ourselves from within the work
53  * function. Because the relative_rate changes so fast, the tag
54  * placement cannot be based on a single factor after the call to
55  * work and must be handled when the samples are and based on the
56  * current resampling rate.
57  */
59  {
60  public:
61  // gr::blocks::test_tag_variable_rate_ff::sptr
62  typedef boost::shared_ptr<test_tag_variable_rate_ff> sptr;
63 
64  /*!
65  * Build a test_tag_variable_rate_ff block.
66  *
67  * \param update_once Update the resampling rate once per call
68  * to work (default=false).
69  * \param update_step How much to adjust the resampling rate by
70  * when the update occurs (default=0.001).
71  */
72  static sptr make(bool update_once=false,
73  double update_step=0.001);
74  };
75 
76  } /* namespace blocks */
77 } /* namespace gr */
78 
79 #endif /* INCLUDED_GR_TEST_TAG_VARIABLE_RATE_FF_H */
Used for testing tag propagation.This block resamples the stream by a factor that starts at 0...
Definition: test_tag_variable_rate_ff.h:58
Include this header to use the message passing features.
Definition: basic_block.h:45
#define BLOCKS_API
Definition: gr-blocks/include/gnuradio/blocks/api.h:30
The abstract base class for all &#39;terminal&#39; processing blocks.A signal processing flow is constructed ...
Definition: block.h:60
boost::shared_ptr< test_tag_variable_rate_ff > sptr
Definition: test_tag_variable_rate_ff.h:62