--- /dev/null
+/* -*- 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_fll_band_edge_cc.h>
+#include <gr_fir_ccc.h>
+#include <gr_fir_util.h>
+#include <gri_fft.h>
+#include <gr_io_signature.h>
+#include <gr_expj.h>
+#include <gr_math.h>
+#include <cstdio>
+
+#define M_TWOPI (2*M_PI)
+
+float sinc(float x)
+{
+ if(x == 0)
+ return 1;
+ else
+ return sin(M_PI*x)/(M_PI*x);
+}
+
+
+
+gr_fll_band_edge_cc_sptr gr_make_fll_band_edge_cc (float samps_per_sym, float rolloff,
+ int filter_size, float gain_alpha, float gain_beta)
+{
+ return gr_fll_band_edge_cc_sptr (new gr_fll_band_edge_cc (samps_per_sym, rolloff,
+ filter_size, gain_alpha, gain_beta));
+}
+
+
+static int ios[] = {sizeof(gr_complex), sizeof(float), sizeof(float), sizeof(gr_complex)};
+static std::vector<int> iosig(ios, ios+sizeof(ios)/sizeof(int));
+gr_fll_band_edge_cc::gr_fll_band_edge_cc (float samps_per_sym, float rolloff,
+ int filter_size, float alpha, float beta)
+ : gr_sync_block ("fll_band_edge_cc",
+ gr_make_io_signature (1, 1, sizeof(gr_complex)),
+ gr_make_io_signaturev (1, 4, iosig)),
+ d_alpha(alpha), d_beta(beta), d_updated (false)
+{
+ // base this on the number of samples per symbol
+ d_max_freq = M_TWOPI * (2.0/samps_per_sym);
+ d_min_freq = -M_TWOPI * (2.0/samps_per_sym);
+
+ d_freq = 0;
+ d_phase = 0;
+
+ set_alpha(alpha);
+
+ design_filter(samps_per_sym, rolloff, filter_size);
+}
+
+gr_fll_band_edge_cc::~gr_fll_band_edge_cc ()
+{
+ delete d_filter_lower;
+ delete d_filter_upper;
+}
+
+void
+gr_fll_band_edge_cc::set_alpha(float alpha)
+{
+ //float eta = sqrt(2.0)/2.0;
+ //float theta = alpha;
+ //d_alpha = (4*eta*theta) / (1.0 + 2.0*eta*theta + theta*theta);
+ //d_beta = (4*theta*theta) / (1.0 + 2.0*eta*theta + theta*theta);
+ d_alpha = alpha;
+}
+
+void
+gr_fll_band_edge_cc::design_filter(float samps_per_sym, float rolloff, int filter_size)
+{
+ int M = rint(filter_size / samps_per_sym);
+ float power = 0;
+ std::vector<float> bb_taps;
+ for(int i = 0; i < filter_size; i++) {
+ float k = -M + i*2.0/samps_per_sym;
+ float tap = sinc(rolloff*k - 0.5) + sinc(rolloff*k + 0.5);
+ power += tap;
+
+ bb_taps.push_back(tap);
+ }
+
+ int N = (bb_taps.size() - 1.0)/2.0;
+ std::vector<gr_complex> taps_lower;
+ std::vector<gr_complex> taps_upper;
+ for(unsigned int i = 0; i < bb_taps.size(); i++) {
+ float tap = bb_taps[i] / power;
+
+ float k = (-N + (int)i)/(2.0*samps_per_sym);
+
+ gr_complex t1 = tap * gr_expj(-2*M_PI*(1+rolloff)*k);
+ gr_complex t2 = tap * gr_expj(2*M_PI*(1+rolloff)*k);
+
+ taps_lower.push_back(t1);
+ taps_upper.push_back(t2);
+ }
+
+ std::vector<gr_complex> vtaps(0, taps_lower.size());
+ d_filter_upper = gr_fir_util::create_gr_fir_ccc(vtaps);
+ d_filter_lower = gr_fir_util::create_gr_fir_ccc(vtaps);
+
+ d_filter_lower->set_taps(taps_lower);
+ d_filter_upper->set_taps(taps_upper);
+
+ d_updated = true;
+
+ // Set the history to ensure enough input items for each filter
+ set_history(filter_size+1);
+
+}
+
+void
+gr_fll_band_edge_cc::print_taps()
+{
+ unsigned int i;
+ std::vector<gr_complex> taps_upper = d_filter_upper->get_taps();
+ std::vector<gr_complex> taps_lower = d_filter_lower->get_taps();
+
+ printf("Upper Band-edge: [");
+ for(i = 0; i < taps_upper.size(); i++) {
+ printf(" %.4e + %.4ej,", taps_upper[i].real(), taps_upper[i].imag());
+ }
+ printf("]\n\n");
+
+ printf("Lower Band-edge: [");
+ for(i = 0; i < taps_lower.size(); i++) {
+ printf(" %.4e + %.4ej,", taps_lower[i].real(), taps_lower[i].imag());
+ }
+ printf("]\n\n");
+}
+
+int
+gr_fll_band_edge_cc::work (int noutput_items,
+ gr_vector_const_void_star &input_items,
+ gr_vector_void_star &output_items)
+{
+ const gr_complex *in = (const gr_complex *) input_items[0];
+ gr_complex *out = (gr_complex *) output_items[0];
+
+ float *frq, *phs;
+ gr_complex *err;
+ if(output_items.size() > 2) {
+ frq = (float *) output_items[1];
+ phs = (float *) output_items[2];
+ err = (gr_complex *) output_items[3];
+ }
+
+ if (d_updated) {
+ d_updated = false;
+ return 0; // history requirements may have changed.
+ }
+
+ int i;
+ gr_complex nco_out;
+ gr_complex out_upper, out_lower;
+ float error;
+ float avg_k = 0.1;
+ for(i = 0; i < noutput_items; i++) {
+ nco_out = gr_expj(d_phase);
+ out[i] = in[i] * nco_out;
+
+ out_upper = (d_filter_upper->filter(&out[i]));
+ out_lower = (d_filter_lower->filter(&out[i]));
+ error = -real((out_upper + out_lower) * conj(out_upper - out_lower));
+ d_error = avg_k*error + avg_k*d_error; // average error
+
+ d_freq = d_freq + d_beta * d_error;
+ d_phase = d_phase + d_freq + d_alpha * d_error;
+
+ if(d_phase > M_PI)
+ d_phase -= M_TWOPI;
+ else if(d_phase < -M_PI)
+ d_phase += M_TWOPI;
+
+ if (d_freq > d_max_freq)
+ d_freq = d_max_freq;
+ else if (d_freq < d_min_freq)
+ d_freq = d_min_freq;
+
+ if(output_items.size() > 2) {
+ frq[i] = d_freq;
+ phs[i] = d_phase;
+ err[i] = d_error;
+ }
+ }
+
+
+ return noutput_items;
+}
projects / debian / gnuradio / blobdiff