GNU Radio Manual and C++ API Reference  3.7.13.4
The Free & Open Software Radio Ecosystem
mmse_fir_interpolator_cc.h
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1 /* -*- c++ -*- */
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3  * Copyright 2002,2007,2012 Free Software Foundation, Inc.
4  *
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22 #ifndef _GRI_MMSE_FIR_INTERPOLATOR_CC_H_
23 #define _GRI_MMSE_FIR_INTERPOLATOR_CC_H_
24 
25 #include <gnuradio/filter/api.h>
27 #include <gnuradio/gr_complex.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 Minimum 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  *
62  * \p input must have ntaps() valid entries and be 8-byte aligned.
63  * input[0] .. input[ntaps() - 1] are referenced to compute the output value.
64  * \throws std::invalid_argument if input is not 8-byte aligned.
65  *
66  * \p mu must be in the range [0, 1] and specifies the fractional delay.
67  *
68  * \returns the interpolated input value.
69  */
70  gr_complex interpolate(const gr_complex input[], float mu) const;
71 
72  protected:
73  std::vector<kernel::fir_filter_ccf *> filters;
74  };
75 
76  } /* namespace filter */
77 } /* namespace gr */
78 
79 #endif /* _MMSE_FIR_INTERPOLATOR_CC_H_ */
std::complex< float > gr_complex
Definition: gr_complex.h:27
Include this header to use the message passing features.
Definition: logger.h:695
std::vector< kernel::fir_filter_ccf * > filters
Definition: mmse_fir_interpolator_cc.h:73
Compute intermediate samples between signal samples x(k*Ts)
Definition: mmse_fir_interpolator_cc.h:50
#define FILTER_API
Definition: gr-filter/include/gnuradio/filter/api.h:30