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/* -*- c++ -*- */
/*
* Copyright 2005,2006,2010-2012,2014 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "clock_recovery_mm_cc_impl.h"
#include <gnuradio/io_signature.h>
#include <gnuradio/math.h>
#include <gnuradio/prefs.h>
#include <iomanip>
#include <sstream>
#include <stdexcept>
namespace gr {
namespace digital {
static const int FUDGE = 16;
clock_recovery_mm_cc::sptr clock_recovery_mm_cc::make(
float omega, float gain_omega, float mu, float gain_mu, float omega_relative_limit)
{
return gnuradio::get_initial_sptr(new clock_recovery_mm_cc_impl(
omega, gain_omega, mu, gain_mu, omega_relative_limit));
}
clock_recovery_mm_cc_impl::clock_recovery_mm_cc_impl(
float omega, float gain_omega, float mu, float gain_mu, float omega_relative_limit)
: block("clock_recovery_mm_cc",
io_signature::make(1, 1, sizeof(gr_complex)),
io_signature::make2(1, 2, sizeof(gr_complex), sizeof(float))),
d_mu(mu),
d_omega(omega),
d_gain_omega(gain_omega),
d_omega_relative_limit(omega_relative_limit),
d_gain_mu(gain_mu),
d_last_sample(0),
d_interp(new filter::mmse_fir_interpolator_cc()),
d_verbose(prefs::singleton()->get_bool("clock_recovery_mm_cc", "verbose", false)),
d_p_2T(0),
d_p_1T(0),
d_p_0T(0),
d_c_2T(0),
d_c_1T(0),
d_c_0T(0)
{
if (omega <= 0.0)
throw std::out_of_range("clock rate must be > 0");
if (gain_mu < 0 || gain_omega < 0)
throw std::out_of_range("Gains must be non-negative");
set_omega(omega); // also sets min and max omega
set_inverse_relative_rate(omega);
set_history(3); // ensure 2 extra input samples are available
enable_update_rate(true); // fixes tag propagation through variable rate block
}
clock_recovery_mm_cc_impl::~clock_recovery_mm_cc_impl() { delete d_interp; }
void clock_recovery_mm_cc_impl::forecast(int noutput_items,
gr_vector_int& ninput_items_required)
{
unsigned ninputs = ninput_items_required.size();
for (unsigned i = 0; i < ninputs; i++)
ninput_items_required[i] =
(int)ceil((noutput_items * d_omega) + d_interp->ntaps()) + FUDGE;
}
gr_complex clock_recovery_mm_cc_impl::slicer_0deg(gr_complex sample)
{
float real = 0, imag = 0;
if (sample.real() > 0)
real = 1;
if (sample.imag() > 0)
imag = 1;
return gr_complex(real, imag);
}
gr_complex clock_recovery_mm_cc_impl::slicer_45deg(gr_complex sample)
{
float real = -1, imag = -1;
if (sample.real() > 0)
real = 1;
if (sample.imag() > 0)
imag = 1;
return gr_complex(real, imag);
}
void clock_recovery_mm_cc_impl::set_omega(float omega)
{
d_omega = omega;
d_omega_mid = omega;
d_omega_lim = d_omega_relative_limit * omega;
}
int clock_recovery_mm_cc_impl::general_work(int noutput_items,
gr_vector_int& ninput_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];
bool write_foptr = output_items.size() >= 2;
int ii = 0; // input index
int oo = 0; // output index
int ni =
ninput_items[0] - d_interp->ntaps() - FUDGE; // don't use more input than this
assert(d_mu >= 0.0);
assert(d_mu <= 1.0);
float mm_val = 0;
gr_complex u, x, y;
// This loop writes the error to the second output, if it exists
if (write_foptr) {
float* foptr = (float*)output_items[1];
while (oo < noutput_items && ii < ni) {
d_p_2T = d_p_1T;
d_p_1T = d_p_0T;
d_p_0T = d_interp->interpolate(&in[ii], d_mu);
d_c_2T = d_c_1T;
d_c_1T = d_c_0T;
d_c_0T = slicer_0deg(d_p_0T);
x = (d_c_0T - d_c_2T) * conj(d_p_1T);
y = (d_p_0T - d_p_2T) * conj(d_c_1T);
u = y - x;
mm_val = u.real();
out[oo++] = d_p_0T;
// limit mm_val
mm_val = gr::branchless_clip(mm_val, 1.0);
d_omega = d_omega + d_gain_omega * mm_val;
d_omega =
d_omega_mid + gr::branchless_clip(d_omega - d_omega_mid, d_omega_lim);
d_mu = d_mu + d_omega + d_gain_mu * mm_val;
ii += (int)floor(d_mu);
d_mu -= floor(d_mu);
// write the error signal to the second output
foptr[oo - 1] = mm_val;
if (ii < 0) // clamp it. This should only happen with bogus input
ii = 0;
}
}
// This loop does not write to the second output (ugly, but faster)
else {
while (oo < noutput_items && ii < ni) {
d_p_2T = d_p_1T;
d_p_1T = d_p_0T;
d_p_0T = d_interp->interpolate(&in[ii], d_mu);
d_c_2T = d_c_1T;
d_c_1T = d_c_0T;
d_c_0T = slicer_0deg(d_p_0T);
x = (d_c_0T - d_c_2T) * conj(d_p_1T);
y = (d_p_0T - d_p_2T) * conj(d_c_1T);
u = y - x;
mm_val = u.real();
out[oo++] = d_p_0T;
// limit mm_val
mm_val = gr::branchless_clip(mm_val, 1.0);
d_omega = d_omega + d_gain_omega * mm_val;
d_omega =
d_omega_mid + gr::branchless_clip(d_omega - d_omega_mid, d_omega_lim);
d_mu = d_mu + d_omega + d_gain_mu * mm_val;
ii += (int)floor(d_mu);
d_mu -= floor(d_mu);
if (d_verbose) {
std::stringstream tmp;
tmp << std::setprecision(8) << std::fixed << d_omega << "\t" << d_mu
<< std::endl;
GR_LOG_INFO(d_logger, tmp.str());
}
if (ii < 0) // clamp it. This should only happen with bogus input
ii = 0;
}
}
if (ii > 0) {
assert(ii <= ninput_items[0]);
consume_each(ii);
}
return oo;
}
} /* namespace digital */
} /* namespace gr */
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