diff options
Diffstat (limited to 'gr-digital/lib/clock_recovery_mm_ff_impl.cc')
| -rw-r--r-- | gr-digital/lib/clock_recovery_mm_ff_impl.cc | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/gr-digital/lib/clock_recovery_mm_ff_impl.cc b/gr-digital/lib/clock_recovery_mm_ff_impl.cc new file mode 100644 index 0000000000..4ac3e40c5d --- /dev/null +++ b/gr-digital/lib/clock_recovery_mm_ff_impl.cc @@ -0,0 +1,120 @@ +/* -*- c++ -*- */ +/* + * Copyright 2004,2010-2012 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 "clock_recovery_mm_ff_impl.h" +#include <gr_io_signature.h> +#include <gr_math.h> +#include <stdexcept> + +namespace gr { + namespace digital { + + clock_recovery_mm_ff::sptr + clock_recovery_mm_ff::make(float omega, float gain_omega, + float mu, float gain_mu, + float omega_relative_limit) + { + return gnuradio::get_initial_sptr + (new clock_recovery_mm_ff_impl(omega, gain_omega, + mu, gain_mu, + omega_relative_limit)); + } + + clock_recovery_mm_ff_impl::clock_recovery_mm_ff_impl(float omega, float gain_omega, + float mu, float gain_mu, + float omega_relative_limit) + : gr_block("clock_recovery_mm_ff", + gr_make_io_signature(1, 1, sizeof(float)), + gr_make_io_signature(1, 1, sizeof(float))), + d_mu(mu), d_gain_mu(gain_mu), d_gain_omega(gain_omega), + d_omega_relative_limit(omega_relative_limit), + d_last_sample(0), d_interp(new filter::mmse_fir_interpolator_ff()) + { + if(omega < 1) + 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_relative_rate (1.0 / omega); + } + + clock_recovery_mm_ff_impl::~clock_recovery_mm_ff_impl() + { + delete d_interp; + } + + void + clock_recovery_mm_ff_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()); + } + + static inline float + slice(float x) + { + return x < 0 ? -1.0F : 1.0F; + } + + int + clock_recovery_mm_ff_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 float *in = (const float *)input_items[0]; + float *out = (float *)output_items[0]; + + int ii = 0; // input index + int oo = 0; // output index + int ni = ninput_items[0] - d_interp->ntaps(); // don't use more input than this + float mm_val; + + while(oo < noutput_items && ii < ni ) { + // produce output sample + out[oo] = d_interp->interpolate(&in[ii], d_mu); + mm_val = slice(d_last_sample) * out[oo] - slice(out[oo]) * d_last_sample; + d_last_sample = out[oo]; + + d_omega = d_omega + d_gain_omega * mm_val; + d_omega = d_omega_mid + gr_branchless_clip(d_omega-d_omega_mid, d_omega_relative_limit); + d_mu = d_mu + d_omega + d_gain_mu * mm_val; + + ii += (int)floor(d_mu); + d_mu = d_mu - floor(d_mu); + oo++; + } + + consume_each(ii); + return oo; + } + + } /* namespace digital */ +} /* namespace gr */ |