diff options
| -rw-r--r-- | gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.cc | 110 | ||||
| -rw-r--r-- | gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.h | 151 | ||||
| -rw-r--r-- | gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.i | 13 |
3 files changed, 231 insertions, 43 deletions
diff --git a/gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.cc b/gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.cc index a52d1d901..7dafe25dd 100644 --- a/gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.cc +++ b/gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.cc @@ -1,6 +1,6 @@ /* -*- c++ -*- */ /* - * Copyright 2009,2010 Free Software Foundation, Inc. + * Copyright 2009-2011 Free Software Foundation, Inc. * * This file is part of GNU Radio * @@ -33,14 +33,14 @@ #include <gr_io_signature.h> #include <gr_math.h> -gr_pfb_clock_sync_ccf_sptr gr_make_pfb_clock_sync_ccf (double sps, float gain, +gr_pfb_clock_sync_ccf_sptr gr_make_pfb_clock_sync_ccf (double sps, float loop_bw, const std::vector<float> &taps, unsigned int filter_size, float init_phase, float max_rate_deviation, int osps) { - return gnuradio::get_initial_sptr(new gr_pfb_clock_sync_ccf (sps, gain, taps, + return gnuradio::get_initial_sptr(new gr_pfb_clock_sync_ccf (sps, loop_bw, taps, filter_size, init_phase, max_rate_deviation, @@ -49,7 +49,7 @@ gr_pfb_clock_sync_ccf_sptr gr_make_pfb_clock_sync_ccf (double sps, float gain, static int ios[] = {sizeof(gr_complex), sizeof(float), sizeof(float), sizeof(float)}; static std::vector<int> iosig(ios, ios+sizeof(ios)/sizeof(int)); -gr_pfb_clock_sync_ccf::gr_pfb_clock_sync_ccf (double sps, float gain, +gr_pfb_clock_sync_ccf::gr_pfb_clock_sync_ccf (double sps, float loop_bw, const std::vector<float> &taps, unsigned int filter_size, float init_phase, @@ -65,11 +65,15 @@ gr_pfb_clock_sync_ccf::gr_pfb_clock_sync_ccf (double sps, float gain, d_nfilters = filter_size; d_sps = floor(sps); + // Set the damping factor for a critically damped system + d_damping = sqrtf(2.0f)/2.0f; + + // Set the bandwidth, which will then call update_gains() + set_loop_bandwidth(loop_bw); + // Store the last filter between calls to work // The accumulator keeps track of overflow to increment the stride correctly. // set it here to the fractional difference based on the initial phaes - set_alpha(gain); - set_beta(0.25*gain*gain); d_k = init_phase; d_rate = (sps-floor(sps))*(double)d_nfilters; d_rate_i = (int)floor(d_rate); @@ -107,6 +111,94 @@ gr_pfb_clock_sync_ccf::check_topology(int ninputs, int noutputs) return noutputs == 1 || noutputs == 4; } + + +/******************************************************************* + SET FUNCTIONS +*******************************************************************/ + + +void +gr_pfb_clock_sync_ccf::set_loop_bandwidth(float bw) +{ + if(bw < 0) { + throw std::out_of_range ("gr_pfb_clock_sync_cc: invalid bandwidth. Must be >= 0."); + } + + d_loop_bw = bw; + update_gains(); +} + +void +gr_pfb_clock_sync_ccf::set_damping_factor(float df) +{ + if(df < 0 || df > 1.0) { + throw std::out_of_range ("gr_pfb_clock_sync_cc: invalid damping factor. Must be in [0,1]."); + } + + d_damping = df; + update_gains(); +} + +void +gr_pfb_clock_sync_ccf::set_alpha(float alpha) +{ + if(alpha < 0 || alpha > 1.0) { + throw std::out_of_range ("gr_pfb_clock_sync_cc: invalid alpha. Must be in [0,1]."); + } + d_alpha = alpha; +} + +void +gr_pfb_clock_sync_ccf::set_beta(float beta) +{ + if(beta < 0 || beta > 1.0) { + throw std::out_of_range ("gr_pfb_clock_sync_cc: invalid beta. Must be in [0,1]."); + } + d_beta = beta; +} + +/******************************************************************* + GET FUNCTIONS +*******************************************************************/ + + +float +gr_pfb_clock_sync_ccf::get_loop_bandwidth() const +{ + return d_loop_bw; +} + +float +gr_pfb_clock_sync_ccf::get_damping_factor() const +{ + return d_damping; +} + +float +gr_pfb_clock_sync_ccf::get_alpha() const +{ + return d_alpha; +} + +float +gr_pfb_clock_sync_ccf::get_beta() const +{ + return d_beta; +} + +/******************************************************************* +*******************************************************************/ + +void +gr_pfb_clock_sync_ccf::update_gains() +{ + float denom = (1.0 + 2.0*d_damping*d_loop_bw + d_loop_bw*d_loop_bw); + d_alpha = (4*d_damping*d_loop_bw) / denom; + d_beta = (4*d_loop_bw*d_loop_bw) / denom; +} + + void gr_pfb_clock_sync_ccf::set_taps (const std::vector<float> &newtaps, std::vector< std::vector<float> > &ourtaps, @@ -271,13 +363,13 @@ gr_pfb_clock_sync_ccf::general_work (int noutput_items, } gr_complex diff = d_diff_filters[d_filtnum]->filter(&in[count]); - error_r = out[i].real() * diff.real(); - error_i = out[i].imag() * diff.imag(); + error_r = tanh(out[i].real()) * diff.real(); + error_i = tanh(out[i].imag()) * diff.imag(); error = (error_i + error_r) / 2.0; // average error from I&Q channel // Run the control loop to update the current phase (k) and tracking rate - d_k = d_k + d_alpha*error + d_rate_i + d_rate_f; d_rate_f = d_rate_f + d_beta*error; + d_k = d_k + d_alpha*error + d_rate_i + d_rate_f; // Keep our rate within a good range d_rate_f = gr_branchless_clip(d_rate_f, d_max_dev); diff --git a/gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.h b/gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.h index d4357e3d8..a869bcf1d 100644 --- a/gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.h +++ b/gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.h @@ -28,7 +28,7 @@ class gr_pfb_clock_sync_ccf; typedef boost::shared_ptr<gr_pfb_clock_sync_ccf> gr_pfb_clock_sync_ccf_sptr; -gr_pfb_clock_sync_ccf_sptr gr_make_pfb_clock_sync_ccf (double sps, float gain, +gr_pfb_clock_sync_ccf_sptr gr_make_pfb_clock_sync_ccf (double sps, float loop_bw, const std::vector<float> &taps, unsigned int filter_size=32, float init_phase=0, @@ -117,7 +117,7 @@ class gr_pfb_clock_sync_ccf : public gr_block /*! * Build the polyphase filterbank timing synchronizer. * \param sps (double) The number of samples per symbol in the incoming signal - * \param gain (float) The alpha gain of the control loop; beta = (gain^2)/4 by default. + * \param loop_bw (float) The bandwidth of the control loop; set's alpha and beta. * \param taps (vector<int>) The filter taps. * \param filter_size (uint) The number of filters in the filterbank (default = 32). * \param init_phase (float) The initial phase to look at, or which filter to start @@ -125,36 +125,40 @@ class gr_pfb_clock_sync_ccf : public gr_block * \param max_rate_deviation (float) Distance from 0 d_rate can get (default = 1.5). * */ - friend gr_pfb_clock_sync_ccf_sptr gr_make_pfb_clock_sync_ccf (double sps, float gain, + friend gr_pfb_clock_sync_ccf_sptr gr_make_pfb_clock_sync_ccf (double sps, float loop_bw, const std::vector<float> &taps, unsigned int filter_size, float init_phase, float max_rate_deviation, int osps); - bool d_updated; - double d_sps; - double d_sample_num; - float d_alpha; - float d_beta; - int d_nfilters; - std::vector<gr_fir_ccf*> d_filters; - std::vector<gr_fir_ccf*> d_diff_filters; + bool d_updated; + double d_sps; + double d_sample_num; + float d_loop_bw; + float d_damping; + float d_alpha; + float d_beta; + + int d_nfilters; + int d_taps_per_filter; + std::vector<gr_fir_ccf*> d_filters; + std::vector<gr_fir_ccf*> d_diff_filters; std::vector< std::vector<float> > d_taps; std::vector< std::vector<float> > d_dtaps; - float d_k; - float d_rate; - float d_rate_i; - float d_rate_f; - float d_max_dev; - int d_filtnum; - int d_taps_per_filter; - int d_osps; + + float d_k; + float d_rate; + float d_rate_i; + float d_rate_f; + float d_max_dev; + int d_filtnum; + int d_osps; /*! * Build the polyphase filterbank timing synchronizer. */ - gr_pfb_clock_sync_ccf (double sps, float gain, + gr_pfb_clock_sync_ccf (double sps, float loop_bw, const std::vector<float> &taps, unsigned int filter_size, float init_phase, @@ -166,6 +170,15 @@ class gr_pfb_clock_sync_ccf : public gr_block public: ~gr_pfb_clock_sync_ccf (); + + /*! \brief update the system gains from omega and eta + * + * This function updates the system gains based on the loop + * bandwidth and damping factor of the system. + * These two factors can be set separately through their own + * set functions. + */ + void update_gains(); /*! * Resets the filterbank's filter taps with the new prototype filter @@ -194,21 +207,68 @@ public: */ void print_diff_taps(); + + /******************************************************************* + SET FUNCTIONS + *******************************************************************/ + + /*! - * Set the gain value alpha for the control loop - */ - void set_alpha(float alpha) - { - d_alpha = alpha; - } + * \brief Set the loop bandwidth + * + * Set the loop filter's bandwidth to \p bw. This should be between + * 2*pi/200 and 2*pi/100 (in rads/samp). It must also be a positive + * number. + * + * When a new damping factor is set, the gains, alpha and beta, of the loop + * are recalculated by a call to update_gains(). + * + * \param bw (float) new bandwidth + * + */ + void set_loop_bandwidth(float bw); /*! - * Set the gain value beta for the control loop - */ - void set_beta(float beta) - { - d_beta = beta; - } + * \brief Set the loop damping factor + * + * Set the loop filter's damping factor to \p df. The damping factor + * should be sqrt(2)/2.0 for critically damped systems. + * Set it to anything else only if you know what you are doing. It must + * be a number between 0 and 1. + * + * When a new damping factor is set, the gains, alpha and beta, of the loop + * are recalculated by a call to update_gains(). + * + * \param df (float) new damping factor + * + */ + void set_damping_factor(float df); + + /*! + * \brief Set the loop gain alpha + * + * Set's the loop filter's alpha gain parameter. + * + * This value should really only be set by adjusting the loop bandwidth + * and damping factor. + * + * \param alpha (float) new alpha gain + * + */ + void set_alpha(float alpha); + + /*! + * \brief Set the loop gain beta + * + * Set's the loop filter's beta gain parameter. + * + * This value should really only be set by adjusting the loop bandwidth + * and damping factor. + * + * \param beta (float) new beta gain + * + */ + void set_beta(float beta); /*! * Set the maximum deviation from 0 d_rate can have @@ -218,6 +278,33 @@ public: d_max_dev = m; } + /******************************************************************* + GET FUNCTIONS + *******************************************************************/ + + /*! + * \brief Returns the loop bandwidth + */ + float get_loop_bandwidth() const; + + /*! + * \brief Returns the loop damping factor + */ + float get_damping_factor() const; + + /*! + * \brief Returns the loop gain alpha + */ + float get_alpha() const; + + /*! + * \brief Returns the loop gain beta + */ + float get_beta() const; + + /******************************************************************* + *******************************************************************/ + bool check_topology(int ninputs, int noutputs); int general_work (int noutput_items, diff --git a/gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.i b/gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.i index 343ed0912..4d7aaec2b 100644 --- a/gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.i +++ b/gnuradio-core/src/lib/filter/gr_pfb_clock_sync_ccf.i @@ -22,7 +22,7 @@ GR_SWIG_BLOCK_MAGIC(gr,pfb_clock_sync_ccf); -gr_pfb_clock_sync_ccf_sptr gr_make_pfb_clock_sync_ccf (double sps, float gain, +gr_pfb_clock_sync_ccf_sptr gr_make_pfb_clock_sync_ccf (double sps, float loop_bw, const std::vector<float> &taps, unsigned int filter_size=32, float init_phase=0, @@ -32,7 +32,7 @@ gr_pfb_clock_sync_ccf_sptr gr_make_pfb_clock_sync_ccf (double sps, float gain, class gr_pfb_clock_sync_ccf : public gr_block { private: - gr_pfb_clock_sync_ccf (double sps, float gain, + gr_pfb_clock_sync_ccf (double sps, float loop_bw, const std::vector<float> &taps, unsigned int filter_size, float init_phase, @@ -50,7 +50,16 @@ class gr_pfb_clock_sync_ccf : public gr_block std::vector<float> diff_channel_taps(int channel); void print_taps(); void print_diff_taps(); + + void set_loop_bandwidth(float bw); + void set_damping_factor(float df); void set_alpha(float alpha); void set_beta(float beta); void set_max_rate_deviation(float m); + + float get_loop_bandwidth() const; + float get_damping_factor() const; + float get_alpha() const; + float get_beta() const; + }; |