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mmse_fir_interpolator_ff.h
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1 /* -*- c++ -*- */
2 /*
3  * Copyright 2002,2012 Free Software Foundation, Inc.
4  *
5  * This file is part of GNU Radio
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7  * GNU Radio is free software; you can redistribute it and/or modify
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15  * GNU General Public License for more details.
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22 
23 #ifndef _MMSE_FIR_INTERPOLATOR_FF_H_
24 #define _MMSE_FIR_INTERPOLATOR_FF_H_
25 
26 #include <gnuradio/filter/api.h>
28 #include <vector>
29 
30 namespace gr {
31  namespace filter {
32 
33  /*!
34  * \brief Compute intermediate samples between signal samples x(k*Ts)
35  * \ingroup filter_primitive
36  *
37  * \details
38  * This implements a Mininum Mean Squared Error interpolator with
39  * 8 taps. It is suitable for signals where the bandwidth of
40  * interest B = 1/(4*Ts) Where Ts is the time between samples.
41  *
42  * Although mu, the fractional delay, is specified as a float, it
43  * is actually quantized. 0.0 <= mu <= 1.0. That is, mu is
44  * quantized in the interpolate method to 32nd's of a sample.
45  *
46  * For more information, in the GNU Radio source code, see:
47  * \li gr-filter/lib/gen_interpolator_taps/README
48  * \li gr-filter/lib/gen_interpolator_taps/praxis.txt
49  */
51  {
52  public:
55 
56  unsigned ntaps() const;
57  unsigned nsteps() const;
58 
59  /*!
60  * \brief compute a single interpolated output value.
61  * \p input must have ntaps() valid entries.
62  * input[0] .. input[ntaps() - 1] are referenced to compute the output value.
63  *
64  * \p mu must be in the range [0, 1] and specifies the fractional delay.
65  *
66  * \returns the interpolated input value.
67  */
68  float interpolate(const float input[], float mu) const;
69 
70  protected:
71  std::vector<kernel::fir_filter_fff*> filters;
72  };
73 
74  } /* namespace filter */
75 } /* namespace gr */
76 
77 #endif /* _MMSE_FIR_INTERPOLATOR_FF_H_ */
std::vector< kernel::fir_filter_fff * > filters
Definition: mmse_fir_interpolator_ff.h:71
Include this header to use the message passing features.
Definition: logger.h:131
Compute intermediate samples between signal samples x(k*Ts)
Definition: mmse_fir_interpolator_ff.h:50
#define FILTER_API
Definition: gr-filter/include/gnuradio/filter/api.h:30