X-Git-Url: https://git.gag.com/?p=debian%2Fgnuradio;a=blobdiff_plain;f=gnuradio-core%2Fsrc%2Flib%2Ffilter%2Fgr_pfb_decimator_ccf.cc;fp=gnuradio-core%2Fsrc%2Flib%2Ffilter%2Fgr_pfb_decimator_ccf.cc;h=e05e18ff2e0f04c38bd3ce6c152402e6876806d5;hp=0000000000000000000000000000000000000000;hb=35e43e8d8c271e6842191cac3fc3f2f88a861183;hpb=ea29b08aeb54227e6628f655ccfdb96fe4d8c378

diff --git a/gnuradio-core/src/lib/filter/gr_pfb_decimator_ccf.cc b/gnuradio-core/src/lib/filter/gr_pfb_decimator_ccf.cc
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+++ b/gnuradio-core/src/lib/filter/gr_pfb_decimator_ccf.cc
@@ -0,0 +1,175 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gr_pfb_decimator_ccf.h>
+#include <gr_fir_ccf.h>
+#include <gr_fir_util.h>
+#include <gri_fft.h>
+#include <gr_io_signature.h>
+#include <gr_expj.h>
+#include <cstdio>
+
+gr_pfb_decimator_ccf_sptr gr_make_pfb_decimator_ccf (unsigned int decim, 
+						     const std::vector<float> &taps,
+						     unsigned int channel)
+{
+  return gr_pfb_decimator_ccf_sptr (new gr_pfb_decimator_ccf (decim, taps, channel));
+}
+
+
+gr_pfb_decimator_ccf::gr_pfb_decimator_ccf (unsigned int decim, 
+					    const std::vector<float> &taps,
+					    unsigned int channel)
+  : gr_sync_block ("pfb_decimator_ccf",
+		   gr_make_io_signature (decim, decim, sizeof(gr_complex)),
+		   gr_make_io_signature (1, 1, sizeof(gr_complex))),
+    d_updated (false)
+{
+  d_rate = decim;
+  d_filters = std::vector<gr_fir_ccf*>(d_rate);
+  d_chan = channel;
+  d_rotator = new gr_complex[d_rate];
+
+  // Create an FIR filter for each channel and zero out the taps
+  std::vector<float> vtaps(0, d_rate);
+  for(unsigned int i = 0; i < d_rate; i++) {
+    d_filters[i] = gr_fir_util::create_gr_fir_ccf(vtaps);
+    d_rotator[i] = gr_expj(i*2*M_PI*d_chan/d_rate);
+  }
+
+  // Now, actually set the filters' taps
+  set_taps(taps);
+
+  // Create the FFT to handle the output de-spinning of the channels
+  d_fft = new gri_fft_complex (d_rate, false);
+}
+
+gr_pfb_decimator_ccf::~gr_pfb_decimator_ccf ()
+{
+  for(unsigned int i = 0; i < d_rate; i++) {
+    delete d_filters[i];
+  }
+}
+
+void
+gr_pfb_decimator_ccf::set_taps (const std::vector<float> &taps)
+{
+  unsigned int i,j;
+
+  unsigned int ntaps = taps.size();
+  d_taps_per_filter = (unsigned int)ceil((double)ntaps/(double)d_rate);
+
+  // Create d_numchan vectors to store each channel's taps
+  d_taps.resize(d_rate);
+
+  // Make a vector of the taps plus fill it out with 0's to fill
+  // each polyphase filter with exactly d_taps_per_filter
+  std::vector<float> tmp_taps;
+  tmp_taps = taps;
+  while((float)(tmp_taps.size()) < d_rate*d_taps_per_filter) {
+    tmp_taps.push_back(0.0);
+  }
+  
+  // Partition the filter
+  for(i = 0; i < d_rate; i++) {
+    // Each channel uses all d_taps_per_filter with 0's if not enough taps to fill out
+    d_taps[i] = std::vector<float>(d_taps_per_filter, 0);
+    for(j = 0; j < d_taps_per_filter; j++) {
+      d_taps[i][j] = tmp_taps[i + j*d_rate];  // add taps to channels in reverse order
+    }
+    
+    // Build a filter for each channel and add it's taps to it
+    d_filters[i]->set_taps(d_taps[i]);
+  }
+
+  // Set the history to ensure enough input items for each filter
+  set_history (d_taps_per_filter);
+
+  d_updated = true;
+}
+
+void
+gr_pfb_decimator_ccf::print_taps()
+{
+  unsigned int i, j;
+  for(i = 0; i < d_rate; i++) {
+    printf("filter[%d]: [", i);
+    for(j = 0; j < d_taps_per_filter; j++) {
+      printf(" %.4e", d_taps[i][j]);
+    }
+    printf("]\n\n");
+  }
+}
+
+#define ROTATEFFT
+
+int
+gr_pfb_decimator_ccf::work (int noutput_items,
+			    gr_vector_const_void_star &input_items,
+			    gr_vector_void_star &output_items)
+{
+  gr_complex *in;
+  gr_complex *out = (gr_complex *) output_items[0];
+
+  if (d_updated) {
+    d_updated = false;
+    return 0;		     // history requirements may have changed.
+  }
+
+  int i;
+  for(i = 0; i < noutput_items; i++) {
+    // Move through filters from bottom to top
+    out[i] = 0;
+    for(int j = d_rate-1; j >= 0; j--) {
+      // Take in the items from the first input stream to d_rate
+      in = (gr_complex*)input_items[d_rate - 1 - j];
+
+      // Filter current input stream from bottom filter to top
+      // The rotate them by expj(j*k*2pi/M) where M is the number of filters
+      // (the decimation rate) and k is the channel number to extract
+      
+      // This is the real math that goes on; we abuse the FFT to do this quickly
+      // for decimation rates > N where N is a small number (~5):
+      //       out[i] += d_filters[j]->filter(&in[i])*gr_expj(j*d_chan*2*M_PI/d_rate);
+#ifdef ROTATEFFT
+      d_fft->get_inbuf()[j] = d_filters[j]->filter(&in[i]);
+#else
+      out[i] += d_filters[j]->filter(&in[i])*d_rotator[i];
+#endif
+    }
+
+#ifdef ROTATEFFT
+    // Perform the FFT to do the complex multiply despinning for all channels
+    d_fft->execute();
+
+    // Select only the desired channel out
+    out[i] = d_fft->get_outbuf()[d_chan];
+#endif
+    
+  }
+  
+  return noutput_items;
+}