/* -*- c++ -*- */ /* * Copyright 2004,2011,2012 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. */ #ifndef INCLUDED_DIGITAL_CLOCK_RECOVERY_MM_FF_H #define INCLUDED_DIGITAL_CLOCK_RECOVERY_MM_FF_H #include <gnuradio/digital/api.h> #include <gnuradio/block.h> namespace gr { namespace digital { /*! * \brief Mueller and Müller (M&M) based clock recovery block with float input, float output. * \ingroup synchronizers_blk * * \details * This implements the Mueller and Müller (M&M) discrete-time * error-tracking synchronizer. * * The peak to peak input signal amplitude must be symmetrical * about zero, as the M&M timing error detector (TED) is a * decision directed TED, and this block uses a symbol decision * slicer referenced at zero. * * The input signal peak amplitude should be controlled to a * consistent level (e.g. +/- 1.0) before this block to achieve * consistent results for given gain settings; as the TED's output * error signal is directly affected by the input amplitude. * * The input signal must have peaks in order for the TED to output * a correct error signal. If the input signal pulses do not have * peaks (e.g. rectangular pulses) the input signal should be * conditioned with a matched pulse filter or other appropriate * filter to peak the input pulses. For a rectangular base pulse * that is N samples wide, the matched filter taps would be * [1.0/float(N)]*N, or in other words a moving average over N * samples. * * This block will output samples at a rate of one sample per * recovered symbol, and is thus not outputting at a constant rate. * * Output symbols are not a subset of input, but may be interpolated. * * See "Digital Communication Receivers: Synchronization, Channel * Estimation and Signal Processing" by Heinrich Meyr, Marc * Moeneclaey, & Stefan Fechtel. ISBN 0-471-50275-8. */ class DIGITAL_API clock_recovery_mm_ff : virtual public block { public: // gr::digital::clock_recovery_mm_ff::sptr typedef boost::shared_ptr<clock_recovery_mm_ff> sptr; /*! * Make a M&M clock recovery block. * * \param omega Initial estimate of samples per symbol * \param gain_omega Gain setting for omega update loop * \param mu Initial estimate of phase of sample * \param gain_mu Gain setting for mu update loop * \param omega_relative_limit maximum relative deviation from omega */ static sptr make(float omega, float gain_omega, float mu, float gain_mu, float omega_relative_limit); virtual float mu() const = 0; virtual float omega() const = 0; virtual float gain_mu() const = 0; virtual float gain_omega() const = 0; virtual void set_verbose(bool verbose) = 0; virtual void set_gain_mu (float gain_mu) = 0; virtual void set_gain_omega (float gain_omega) = 0; virtual void set_mu (float mu) = 0; virtual void set_omega (float omega) = 0; }; } /* namespace digital */ } /* namespace gr */ #endif /* INCLUDED_DIGITAL_CLOCK_RECOVERY_MM_FF_H */