--- /dev/null
+/* -*- c++ -*- */
+/*
+ * Copyright 2009,2010 Free Software Foundation, Inc.
+ *
+ * This file is part of GNU Radio
+ *
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ *
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING. If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+
+#ifndef INCLUDED_GR_PFB_CHANNELIZER_CCF_H
+#define INCLUDED_GR_PFB_CHANNELIZER_CCF_H
+
+#include <gr_block.h>
+
+class gr_pfb_channelizer_ccf;
+typedef boost::shared_ptr<gr_pfb_channelizer_ccf> gr_pfb_channelizer_ccf_sptr;
+gr_pfb_channelizer_ccf_sptr gr_make_pfb_channelizer_ccf (unsigned int numchans,
+ const std::vector<float> &taps,
+ float oversample_rate=1);
+
+class gr_fir_ccf;
+class gri_fft_complex;
+
+
+/*!
+ * \class gr_pfb_channelizer_ccf
+ *
+ * \brief Polyphase filterbank channelizer with
+ * gr_complex input, gr_complex output and float taps
+ *
+ * \ingroup filter_blk
+ *
+ * This block takes in complex inputs and channelizes it to <EM>M</EM>
+ * channels of equal bandwidth. Each of the resulting channels is
+ * decimated to the new rate that is the input sampling rate
+ * <EM>fs</EM> divided by the number of channels, <EM>M</EM>.
+ *
+ * The PFB channelizer code takes the taps generated above and builds
+ * a set of filters. The set contains <EM>M</EM> number of filters
+ * and each filter contains ceil(taps.size()/decim) number of taps.
+ * Each tap from the filter prototype is sequentially inserted into
+ * the next filter. When all of the input taps are used, the remaining
+ * filters in the filterbank are filled out with 0's to make sure each
+ * filter has the same number of taps.
+ *
+ * Each filter operates using the gr_fir filter classs of GNU Radio,
+ * which takes the input stream at <EM>i</EM> and performs the inner
+ * product calculation to <EM>i+(n-1)</EM> where <EM>n</EM> is the
+ * number of filter taps. To efficiently handle this in the GNU Radio
+ * structure, each filter input must come from its own input
+ * stream. So the channelizer must be provided with <EM>M</EM> streams
+ * where the input stream has been deinterleaved. This is most easily
+ * done using the gr_stream_to_streams block.
+ *
+ * The output is then produced as a vector, where index <EM>i</EM> in
+ * the vector is the next sample from the <EM>i</EM>th channel. This
+ * is most easily handled by sending the output to a
+ * gr_vector_to_streams block to handle the conversion and passing
+ * <EM>M</EM> streams out.
+ *
+ * The input and output formatting is done using a hier_block2 called
+ * pfb_channelizer_ccf. This can take in a single stream and outputs
+ * <EM>M</EM> streams based on the behavior described above.
+ *
+ * The filter's taps should be based on the input sampling rate.
+ *
+ * For example, using the GNU Radio's firdes utility to building
+ * filters, we build a low-pass filter with a sampling rate of
+ * <EM>fs</EM>, a 3-dB bandwidth of <EM>BW</EM> and a transition
+ * bandwidth of <EM>TB</EM>. We can also specify the out-of-band
+ * attenuation to use, <EM>ATT</EM>, and the filter window
+ * function (a Blackman-harris window in this case). The first input
+ * is the gain of the filter, which we specify here as unity.
+ *
+ * <B><EM>self._taps = gr.firdes.low_pass_2(1, fs, BW, TB,
+ * attenuation_dB=ATT, window=gr.firdes.WIN_BLACKMAN_hARRIS)</EM></B>
+ *
+ * The filter output can also be overs ampled. The over sampling rate
+ * is the ratio of the the actual output sampling rate to the normal
+ * output sampling rate. It must be rationally related to the number
+ * of channels as N/i for i in [1,N], which gives an outputsample rate
+ * of [fs/N, fs] where fs is the input sample rate and N is the number
+ * of channels.
+ *
+ * For example, for 6 channels with fs = 6000 Hz, the normal rate is
+ * 6000/6 = 1000 Hz. Allowable oversampling rates are 6/6, 6/5, 6/4,
+ * 6/3, 6/2, and 6/1 where the output sample rate of a 6/1 oversample
+ * ratio is 6000 Hz, or 6 times the normal 1000 Hz. A rate of 6/5 = 1.2,
+ * so the output rate would be 1200 Hz.
+ *
+ * The theory behind this block can be found in Chapter 6 of
+ * the following book.
+ *
+ * <B><EM>f. harris, "Multirate Signal Processing for Communication
+ * Systems," Upper Saddle River, NJ: Prentice Hall, Inc. 2004.</EM></B>
+ *
+ */
+
+class gr_pfb_channelizer_ccf : public gr_block
+{
+ private:
+ /*!
+ * Build the polyphase filterbank decimator.
+ * \param numchans (unsigned integer) Specifies the number of channels <EM>M</EM>
+ * \param taps (vector/list of floats) The prototype filter to populate the filterbank.
+ * \param oversample_rate (float) The over sampling rate is the ratio of the the actual
+ * output sampling rate to the normal output sampling rate.
+ * It must be rationally related to the number of channels
+ * as N/i for i in [1,N], which gives an outputsample rate
+ * of [fs/N, fs] where fs is the input sample rate and N is
+ * the number of channels.
+ *
+ * For example, for 6 channels with fs = 6000 Hz, the normal
+ * rate is 6000/6 = 1000 Hz. Allowable oversampling rates
+ * are 6/6, 6/5, 6/4, 6/3, 6/2, and 6/1 where the output
+ * sample rate of a 6/1 oversample ratio is 6000 Hz, or
+ * 6 times the normal 1000 Hz.
+ */
+ friend gr_pfb_channelizer_ccf_sptr gr_make_pfb_channelizer_ccf (unsigned int numchans,
+ const std::vector<float> &taps,
+ float oversample_rate);
+
+ bool d_updated;
+ unsigned int d_numchans;
+ float d_oversample_rate;
+ std::vector<gr_fir_ccf*> d_filters;
+ std::vector< std::vector<float> > d_taps;
+ unsigned int d_taps_per_filter;
+ gri_fft_complex *d_fft;
+ int *d_idxlut;
+ int d_rate_ratio;
+ int d_output_multiple;
+
+ /*!
+ * Build the polyphase filterbank decimator.
+ * \param numchans (unsigned integer) Specifies the number of channels <EM>M</EM>
+ * \param taps (vector/list of floats) The prototype filter to populate the filterbank.
+ * \param oversample_rate (float) The output over sampling rate.
+ */
+ gr_pfb_channelizer_ccf (unsigned int numchans,
+ const std::vector<float> &taps,
+ float oversample_rate);
+
+public:
+ ~gr_pfb_channelizer_ccf ();
+
+ /*!
+ * Resets the filterbank's filter taps with the new prototype filter
+ * \param taps (vector/list of floats) The prototype filter to populate the filterbank.
+ */
+ void set_taps (const std::vector<float> &taps);
+
+ /*!
+ * Print all of the filterbank taps to screen.
+ */
+ void print_taps();
+
+ int general_work (int noutput_items,
+ gr_vector_int &ninput_items,
+ gr_vector_const_void_star &input_items,
+ gr_vector_void_star &output_items);
+};
+
+#endif
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