/* -*- c++ -*- */
/*
- * Copyright 2009 Free Software Foundation, Inc.
+ * Copyright 2009,2010 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
#include <gri_fft.h>
#include <gr_io_signature.h>
#include <cstdio>
+#include <cstring>
gr_pfb_channelizer_ccf_sptr gr_make_pfb_channelizer_ccf (unsigned int numchans,
- const std::vector<float> &taps)
+ const std::vector<float> &taps,
+ float oversample_rate)
{
- return gr_pfb_channelizer_ccf_sptr (new gr_pfb_channelizer_ccf (numchans, taps));
+ return gnuradio::get_initial_sptr(new gr_pfb_channelizer_ccf (numchans, taps,
+ oversample_rate));
}
gr_pfb_channelizer_ccf::gr_pfb_channelizer_ccf (unsigned int numchans,
- const std::vector<float> &taps)
- : gr_sync_block ("pfb_channelizer_ccf",
- gr_make_io_signature (numchans, numchans, sizeof(gr_complex)),
- gr_make_io_signature (1, 1, numchans*sizeof(gr_complex))),
- d_updated (false)
+ const std::vector<float> &taps,
+ float oversample_rate)
+ : gr_block ("pfb_channelizer_ccf",
+ gr_make_io_signature (numchans, numchans, sizeof(gr_complex)),
+ gr_make_io_signature (1, 1, numchans*sizeof(gr_complex))),
+ d_updated (false), d_numchans(numchans), d_oversample_rate(oversample_rate)
{
- d_numchans = numchans;
+ // The over sampling rate must be rationally related to the number of channels
+ // in that it must be N/i for i in [1,N], which gives an outputsample rate
+ // of [fs/N, fs] where fs is the input sample rate.
+ // This tests the specified input sample rate to see if it conforms to this
+ // requirement within a few significant figures.
+ double intp = 0;
+ double fltp = modf(numchans / oversample_rate, &intp);
+ if(fltp != 0.0)
+ throw std::invalid_argument("gr_pfb_channelizer: oversample rate must be N/i for i in [1, N]");
+
+ set_relative_rate(1.0/intp);
+
d_filters = std::vector<gr_fir_ccf*>(d_numchans);
// Create an FIR filter for each channel and zero out the taps
// Create the FFT to handle the output de-spinning of the channels
d_fft = new gri_fft_complex (d_numchans, false);
+
+ // Although the filters change, we use this look up table
+ // to set the index of the FFT input buffer, which equivalently
+ // performs the FFT shift operation on every other turn.
+ d_rate_ratio = (int)rintf(d_numchans / d_oversample_rate);
+ d_idxlut = new int[d_numchans];
+ for(unsigned int i = 0; i < d_numchans; i++) {
+ d_idxlut[i] = d_numchans - ((i + d_rate_ratio) % d_numchans) - 1;
+ }
+
+ // Calculate the number of filtering rounds to do to evenly
+ // align the input vectors with the output channels
+ d_output_multiple = 1;
+ while((d_output_multiple * d_rate_ratio) % d_numchans != 0)
+ d_output_multiple++;
+ set_output_multiple(d_output_multiple);
}
gr_pfb_channelizer_ccf::~gr_pfb_channelizer_ccf ()
{
+ delete [] d_idxlut;
+
for(unsigned int i = 0; i < d_numchans; i++) {
delete d_filters[i];
}
}
// Set the history to ensure enough input items for each filter
- set_history (d_taps_per_filter);
+ set_history (d_taps_per_filter+1);
d_updated = true;
}
int
-gr_pfb_channelizer_ccf::work (int noutput_items,
- gr_vector_const_void_star &input_items,
- gr_vector_void_star &output_items)
+gr_pfb_channelizer_ccf::general_work (int noutput_items,
+ gr_vector_int &ninput_items,
+ gr_vector_const_void_star &input_items,
+ gr_vector_void_star &output_items)
{
gr_complex *in = (gr_complex *) input_items[0];
gr_complex *out = (gr_complex *) output_items[0];
return 0; // history requirements may have changed.
}
- for(int i = 0; i < noutput_items; i++) {
- // Move through filters from bottom to top
- for(int j = d_numchans-1; j >= 0; j--) {
- // Take in the items from the first input stream to d_numchans
- in = (gr_complex*)input_items[d_numchans - 1 - j];
+ int n=1, i=-1, j=0, last;
+ int toconsume = (int)rintf(noutput_items/d_oversample_rate);
+ while(n <= toconsume) {
+ j = 0;
+ i = (i + d_rate_ratio) % d_numchans;
+ last = i;
+ while(i >= 0) {
+ in = (gr_complex*)input_items[j];
+ d_fft->get_inbuf()[d_idxlut[j]] = d_filters[i]->filter(&in[n]);
+ j++;
+ i--;
+ }
- // Filter current input stream from bottom filter to top
- d_fft->get_inbuf()[j] = d_filters[j]->filter(&in[i]);
+ i = d_numchans-1;
+ while(i > last) {
+ in = (gr_complex*)input_items[j];
+ d_fft->get_inbuf()[d_idxlut[j]] = d_filters[i]->filter(&in[n-1]);
+ j++;
+ i--;
}
+ n += (i+d_rate_ratio) >= (int)d_numchans;
+
// despin through FFT
d_fft->execute();
- memcpy(&out[d_numchans*i], d_fft->get_outbuf(), d_numchans*sizeof(gr_complex));
+ memcpy(out, d_fft->get_outbuf(), d_numchans*sizeof(gr_complex));
+ out += d_numchans;
}
-
+
+ consume_each(toconsume);
return noutput_items;
}
projects / debian / gnuradio / blobdiff