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/* -*- c++ -*- */
/*
* Gqrx SDR: Software defined radio receiver powered by GNU Radio and Qt
* http://gqrx.dk/
*
* Copyright 2011 Alexandru Csete OZ9AEC.
*
* Gqrx 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.
*
* Gqrx 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 Gqrx; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#include <cmath>
#include <gnuradio/io_signature.h>
#include <gnuradio/filter/firdes.h>
#include <iostream>
#include "dsp/rx_filter.h"
static const int MIN_IN = 1; /* Mininum number of input streams. */
static const int MAX_IN = 1; /* Maximum number of input streams. */
static const int MIN_OUT = 1; /* Minimum number of output streams. */
static const int MAX_OUT = 1; /* Maximum number of output streams. */
/*
* Create a new instance of rx_filter and return
* a boost shared_ptr. This is effectively the public constructor.
*/
rx_filter_sptr make_rx_filter(double sample_rate, double low, double high, double trans_width)
{
return gnuradio::get_initial_sptr(new rx_filter(sample_rate, low, high, trans_width));
}
rx_filter::rx_filter(double sample_rate, double low, double high, double trans_width)
: gr::hier_block2 ("rx_filter",
gr::io_signature::make (MIN_IN, MAX_IN, sizeof (gr_complex)),
gr::io_signature::make (MIN_OUT, MAX_OUT, sizeof (gr_complex))),
d_sample_rate(sample_rate),
d_low(low),
d_high(high),
d_trans_width(trans_width)
{
if (low < -0.95*sample_rate/2.0)
d_low = -0.95*sample_rate/2.0;
if (high > 0.95*sample_rate/2.0)
d_high = 0.95*sample_rate/2.0;
/* generate taps */
d_taps = gr::filter::firdes::complex_band_pass(1.0, d_sample_rate, d_low, d_high, d_trans_width);
/* create band pass filter */
d_bpf = gr::filter::fir_filter_ccc::make(1, d_taps);
/* connect filter */
connect(self(), 0, d_bpf, 0);
connect(d_bpf, 0, self(), 0);
}
rx_filter::~rx_filter ()
{
}
void rx_filter::set_param(double low, double high, double trans_width)
{
d_trans_width = trans_width;
d_low = low;
d_high = high;
if (d_low < -0.95*d_sample_rate/2.0)
d_low = -0.95*d_sample_rate/2.0;
if (d_high > 0.95*d_sample_rate/2.0)
d_high = 0.95*d_sample_rate/2.0;
/* generate new taps */
d_taps = gr::filter::firdes::complex_band_pass(1.0, d_sample_rate, d_low, d_high, d_trans_width);
#ifndef QT_NO_DEBUG_OUTPUT
std::cout << "Genrating taps for new filter LO:" << d_low <<
" HI:" << d_high << " TW:" << d_trans_width << std::endl;
std::cout << "Required number of taps: " << d_taps.size() << std::endl;
#endif
d_bpf->set_taps(d_taps);
}
/** Frequency translating filter **/
/*
* Create a new instance of rx_xlating_filter and return
* a boost shared_ptr. This is effectively the public constructor.
*/
rx_xlating_filter_sptr make_rx_xlating_filter(double sample_rate, double center, double low, double high, double trans_width)
{
return gnuradio::get_initial_sptr(new rx_xlating_filter(sample_rate, center, low, high, trans_width));
}
rx_xlating_filter::rx_xlating_filter(double sample_rate, double center, double low, double high, double trans_width)
: gr::hier_block2 ("rx_xlating_filter",
gr::io_signature::make (MIN_IN, MAX_IN, sizeof (gr_complex)),
gr::io_signature::make (MIN_OUT, MAX_OUT, sizeof (gr_complex))),
d_sample_rate(sample_rate),
d_center(center),
d_low(low),
d_high(high),
d_trans_width(trans_width)
{
/* generate taps */
d_taps = gr::filter::firdes::complex_band_pass(1.0, d_sample_rate, -d_high, -d_low, d_trans_width);
/* create band pass filter */
d_bpf = gr::filter::freq_xlating_fir_filter_ccc::make(1, d_taps, d_center, d_sample_rate);
/* connect filter */
connect(self(), 0, d_bpf, 0);
connect(d_bpf, 0, self(), 0);
}
rx_xlating_filter::~rx_xlating_filter()
{
}
void rx_xlating_filter::set_offset(double center)
{
/* we have to change sign because the set_center_freq() actually
shifts the passband with the specified amount, which has
opposite sign of selecting a center frequency.
*/
d_center = -center;
d_bpf->set_center_freq(d_center);
}
void rx_xlating_filter::set_param(double low, double high, double trans_width)
{
d_trans_width = trans_width;
d_low = low;
d_high = high;
/* generate new taps */
d_taps = gr::filter::firdes::complex_band_pass(1.0, d_sample_rate, -d_high, -d_low, d_trans_width);
d_bpf->set_taps(d_taps);
}
void rx_xlating_filter::set_param(double center, double low, double high, double trans_width)
{
set_offset(center);
set_param(low, high, trans_width);
}
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