GNU Radio Manual and C++ API Reference  3.7.13.4
The Free & Open Software Radio Ecosystem
pfb_synthesizer_ccf.h
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22 
23 
24 #ifndef INCLUDED_PFB_SYNTHESIZER_CCF_H
25 #define INCLUDED_PFB_SYNTHESIZER_CCF_H
26 
27 #include <gnuradio/filter/api.h>
29 
30 namespace gr {
31  namespace filter {
32 
33  /*!
34  * \brief Polyphase synthesis filterbank with
35  * gr_complex input, gr_complex output and float taps
36  * \ingroup channelizers_blk
37  *
38  * \details
39  *
40  * The PFB synthesis filterbank combines multiple baseband signals
41  * into a single channelized signal. Each input stream is,
42  * essentially, modulated onto an output channel according the the
43  * channel mapping (see set_channel_map for details).
44  *
45  * Setting this filterbank up means selecting the number of output
46  * channels, the prototype filter, and whether to handle channels
47  * at 2x the sample rate (this is generally used only for
48  * reconstruction filtering).
49  *
50  * The number of channels sets the maximum number of channels to
51  * use, but not all input streams must be connected. For M total
52  * channels, we can connect inputs 0 to N where N < M-1. Because
53  * of the way GNU Radio handles stream connections, we must
54  * connect the channels consecutively, and so we must use the
55  * set_channel_map if the desired output channels are not the same
56  * as the the default mapping. This features gives us the
57  * flexibility to output to any given channel. Generally, we try
58  * to not use the channels at the edge of the spectrum to avoid
59  * issues with filtering and roll-off of the transmitter or
60  * receiver.
61  *
62  * When using the 2x sample rate mode, we specify the number of
63  * channels that will be used. However, the actual output signal
64  * will be twice this number of channels. This is mainly important
65  * to know when setting the channel map. For M channels, the
66  * channel mapping can specy from 0 to 2M-1 channels to output
67  * onto.
68  *
69  * For more details about this and the concepts of reconstruction
70  * filtering, see:
71  *
72  * <B><EM>f. harris, "Multirate Signal Processing for Communication
73  * Systems," Upper Saddle River, NJ: Prentice Hall, Inc. 2004.</EM></B>
74  *
75  * <B><EM>X. Chen, E. Venosa, and fred harris, “Polyphase analysis
76  * filter bank up-converts unequal channel bandwidths with
77  * arbitrary center frequencies - design ii,” in SDR’10-WinnComm,
78  * 2010.</EM></B>
79  *
80  * <B><EM>E. Venosa, X. Chen, and fred harris, “Polyphase analysis
81  * filter bank down-converts unequal channel bandwidths with
82  * arbitrary center frequencies - design I,” in SDR’10-WinnComm,
83  * 2010.</EM></B>
84  *
85  * <B><EM>f. j. harris, C. Dick, X. Chen, and E. Venosa, “Wideband 160-
86  * channel polyphase filter bank cable TV channeliser,” in IET
87  * Signal Processing, 2010.</EM></B>
88  */
90  {
91  public:
92  // gr::filter::pfb_synthesizer_ccf::sptr
93  typedef boost::shared_ptr<pfb_synthesizer_ccf> sptr;
94 
95  /*!
96  * Build the polyphase synthesis filterbank.
97  * \param numchans (unsigned integer) Specifies the number of
98  * channels <EM>M</EM>
99  * \param taps (vector/list of floats) The prototype filter to
100  * populate the filterbank.
101  * \param twox (bool) use 2x oversampling or not (default is no)
102  */
103  static sptr make(unsigned int numchans,
104  const std::vector<float> &taps,
105  bool twox=false);
106 
107  /*!
108  * Resets the filterbank's filter taps with the new prototype filter
109  * \param taps (vector/list of floats) The prototype filter to
110  * populate the filterbank.
111  */
112  virtual void set_taps(const std::vector<float> &taps) = 0;
113 
114  /*!
115  * Print all of the filterbank taps to screen.
116  */
117  virtual void print_taps() = 0;
118 
119  /*!
120  * Return a vector<vector<>> of the filterbank taps
121  */
122  virtual std::vector<std::vector<float> > taps() const = 0;
123 
124  /*!
125  * Set the channel map. Channels are numbers as:
126  * <pre>
127  * N/2+1 | ... | N-1 | 0 | 1 | 2 | ... | N/2
128  * <------------------- 0 -------------------->
129  * freq
130  * </pre>
131  *
132  * So input stream 0 goes to channel 0, etc. Setting a new channel
133  * map allows the user to specify where in frequency he/she wants
134  * the input stream to go. This is especially useful to avoid
135  * putting signals into the channels on the edge of the spectrum
136  * which can either wrap around (in the case of odd number of
137  * channels) and be affected by filter rolloff in the transmitter.
138  *
139  * The map must be at least the number of streams being sent to the
140  * block. Less and the algorithm will not have enough data to
141  * properly setup the buffers. Any more channels specified will be
142  * ignored.
143  */
144  virtual void set_channel_map(const std::vector<int> &map) = 0;
145 
146  /*!
147  * Gets the current channel map.
148  */
149  virtual std::vector<int> channel_map() const = 0;
150  };
151 
152  } /* namespace filter */
153 } /* namespace gr */
154 
155 #endif /* INCLUDED_PFB_SYNTHESIZER_CCF_H */
boost::shared_ptr< pfb_synthesizer_ccf > sptr
Definition: pfb_synthesizer_ccf.h:93
synchronous 1:N input to output with historyOverride work to provide the signal processing implementa...
Definition: sync_interpolator.h:37
Include this header to use the message passing features.
Definition: logger.h:695
PMT_API pmt_t map(pmt_t proc(const pmt_t &), pmt_t list)
Apply proc element-wise to the elements of list and returns a list of the results, in order.
Polyphase synthesis filterbank with gr_complex input, gr_complex output and float taps...
Definition: pfb_synthesizer_ccf.h:89
static const float taps[NSTEPS+1][NTAPS]
Definition: interpolator_taps.h:9
#define FILTER_API
Definition: gr-filter/include/gnuradio/filter/api.h:30