GNU Radio 3.5.1 C++ API
digital_clock_recovery_mm_ff.h
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00001 /* -*- c++ -*- */
00002 /*
00003  * Copyright 2004,2011 Free Software Foundation, Inc.
00004  *
00005  * This file is part of GNU Radio
00006  *
00007  * GNU Radio is free software; you can redistribute it and/or modify
00008  * it under the terms of the GNU General Public License as published by
00009  * the Free Software Foundation; either version 3, or (at your option)
00010  * any later version.
00011  *
00012  * GNU Radio is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015  * GNU General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU General Public License
00018  * along with GNU Radio; see the file COPYING.  If not, write to
00019  * the Free Software Foundation, Inc., 51 Franklin Street,
00020  * Boston, MA 02110-1301, USA.
00021  */
00022 
00023 #ifndef INCLUDED_DIGITAL_CLOCK_RECOVERY_MM_FF_H
00024 #define INCLUDED_DIGITAL_CLOCK_RECOVERY_MM_FF_H
00025 
00026 #include <digital_api.h>
00027 #include <gr_block.h>
00028 #include <gr_math.h>
00029 #include <stdio.h>
00030 
00031 class gri_mmse_fir_interpolator;
00032 
00033 class digital_clock_recovery_mm_ff;
00034 typedef boost::shared_ptr<digital_clock_recovery_mm_ff> digital_clock_recovery_mm_ff_sptr;
00035 
00036 // public constructor
00037 DIGITAL_API digital_clock_recovery_mm_ff_sptr 
00038 digital_make_clock_recovery_mm_ff (float omega, float gain_omega,
00039                                    float mu, float gain_mu,
00040                                    float omega_relative_limit=0.001);
00041 
00042 /*!
00043  * \brief Mueller and Müller (M&M) based clock recovery block with float input, float output.
00044  * \ingroup sync_blk
00045  * \ingroup digital
00046  *
00047  * This implements the Mueller and Müller (M&M) discrete-time error-tracking synchronizer.
00048  *
00049  * See "Digital Communication Receivers: Synchronization, Channel
00050  * Estimation and Signal Processing" by Heinrich Meyr, Marc Moeneclaey, & Stefan Fechtel.
00051  * ISBN 0-471-50275-8.
00052  */
00053 class DIGITAL_API digital_clock_recovery_mm_ff : public gr_block
00054 {
00055  public:
00056   ~digital_clock_recovery_mm_ff ();
00057   void forecast(int noutput_items, gr_vector_int &ninput_items_required);
00058   int general_work (int noutput_items,
00059                     gr_vector_int &ninput_items,
00060                     gr_vector_const_void_star &input_items,
00061                     gr_vector_void_star &output_items);
00062   float mu() const { return d_mu;}
00063   float omega() const { return d_omega;}
00064   float gain_mu() const { return d_gain_mu;}
00065   float gain_omega() const { return d_gain_omega;}
00066 
00067   void set_gain_mu (float gain_mu) { d_gain_mu = gain_mu; }
00068   void set_gain_omega (float gain_omega) { d_gain_omega = gain_omega; }
00069   void set_mu (float mu) { d_mu = mu; }
00070   void set_omega (float omega){
00071     d_omega = omega;
00072     d_min_omega = omega*(1.0 - d_omega_relative_limit);
00073     d_max_omega = omega*(1.0 + d_omega_relative_limit);
00074     d_omega_mid = 0.5*(d_min_omega+d_max_omega);
00075   }
00076 
00077 protected:
00078   digital_clock_recovery_mm_ff (float omega, float gain_omega, float mu, float gain_mu,
00079                            float omega_relative_limit);
00080 
00081  private:
00082   float                         d_mu;           // fractional sample position [0.0, 1.0]
00083   float                         d_omega;        // nominal frequency
00084   float                         d_min_omega;    // minimum allowed omega 
00085   float                         d_omega_mid;    // average omega
00086   float                         d_max_omega;    // maximum allowed omega
00087   float                         d_gain_omega;   // gain for adjusting omega
00088   float                         d_gain_mu;      // gain for adjusting mu
00089   float                         d_last_sample;
00090   gri_mmse_fir_interpolator     *d_interp;
00091   FILE                          *d_logfile;
00092   float                         d_omega_relative_limit; // used to compute min and max omega
00093 
00094   friend DIGITAL_API digital_clock_recovery_mm_ff_sptr
00095   digital_make_clock_recovery_mm_ff (float omega, float gain_omega,
00096                                      float mu, float gain_mu,
00097                                      float omega_relative_limit);
00098 };
00099 
00100 #endif