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/* -*- 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 <noaa_hrpt_pll_cf.h>
#include <gr_io_signature.h>
#include <gr_math.h>
#include <gr_sincos.h>
#define M_TWOPI (2*M_PI)
noaa_hrpt_pll_cf_sptr
noaa_make_hrpt_pll_cf(float alpha, float beta, float max_offset)
{
return gnuradio::get_initial_sptr(new noaa_hrpt_pll_cf(alpha, beta, max_offset));
}
noaa_hrpt_pll_cf::noaa_hrpt_pll_cf(float alpha, float beta, float max_offset)
: gr_sync_block("noaa_hrpt_pll_cf",
gr_make_io_signature(1, 1, sizeof(gr_complex)),
gr_make_io_signature(1, 1, sizeof(float))),
d_alpha(alpha), d_beta(beta), d_max_offset(max_offset),
d_phase(0.0), d_freq(0.0)
{
}
float
phase_wrap(float phase)
{
while (phase < -M_PI)
phase += M_TWOPI;
while (phase > M_PI)
phase -= M_TWOPI;
return phase;
}
int
noaa_hrpt_pll_cf::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];
float *out = (float *) output_items[0];
for (int i = 0; i < noutput_items; i++) {
// Adjust PLL phase/frequency
float error = phase_wrap(gr_fast_atan2f(in[i].imag(), in[i].real()) - d_phase);
d_freq = gr_branchless_clip(d_freq + error*d_beta, d_max_offset);
d_phase = phase_wrap(d_phase + error*d_alpha + d_freq);
// Generate and mix out carrier
float re, im;
gr_sincosf(d_phase, &im, &re);
out[i] = (in[i]*gr_complex(re, -im)).imag();
}
return noutput_items;
}
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