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https://github.com/gnss-sdr/gnss-sdr
synced 2024-12-15 04:30:33 +00:00
Improved Notch Filter Lite
Updated version of the filter
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@ -53,6 +53,10 @@ NotchFilter::NotchFilter(ConfigurationInterface* configuration, std::string role
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float default_p_c_factor = 0.9;
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int length_;
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int default_length_ = 32;
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int n_segments_est;
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int default_n_segments_est = 12500;
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int n_segments_reset;
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int default_n_segments_reset = 5000000;
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std::string default_item_type = "gr_complex";
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std::string default_dump_file = "./data/input_filter.dat";
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item_type_ = configuration->property(role + ".item_type", default_item_type);
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@ -62,10 +66,12 @@ NotchFilter::NotchFilter(ConfigurationInterface* configuration, std::string role
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pfa = configuration->property(role + ".pfa", default_pfa);
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p_c_factor = configuration->property(role + ".p_c_factor", default_p_c_factor);
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length_ = configuration->property(role + ".length", default_length_);
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n_segments_est = configuration->property(role + ".segments_est", default_n_segments_est);
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n_segments_reset = configuration->property(role + ".segments_reset", default_n_segments_reset);
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if (item_type_.compare("gr_complex") == 0)
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{
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item_size_ = sizeof(gr_complex);
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notch_filter_ = make_notch_filter(pfa, p_c_factor, length_);
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notch_filter_ = make_notch_filter(pfa, p_c_factor, length_, n_segments_est, n_segments_reset);
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DLOG(INFO) << "Item size " << item_size_;
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DLOG(INFO) << "input filter(" << notch_filter_->unique_id() << ")";
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@ -31,6 +31,7 @@
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#include "notch_filter_lite.h"
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#include <string>
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#include <cmath>
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#include <memory>
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#include <vector>
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#include <boost/lexical_cast.hpp>
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@ -49,6 +50,18 @@ NotchFilterLite::NotchFilterLite(ConfigurationInterface* configuration, std::str
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size_t item_size_;
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float p_c_factor;
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float default_p_c_factor = 0.9;
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float pfa;
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float default_pfa = 0.001;
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int length_;
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int default_length_ = 32;
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int n_segments_est;
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int default_n_segments_est = 12500;
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int n_segments_reset;
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int default_n_segments_reset = 5000000;
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float default_samp_freq = 4000000;
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float samp_freq = configuration->property("SignalSource.sampling_frequency", default_samp_freq);
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float default_coeff_rate = samp_freq * 0.1;
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float coeff_rate;
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std::string default_item_type = "gr_complex";
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std::string default_dump_file = "./data/input_filter.dat";
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item_type_ = configuration->property(role + ".item_type", default_item_type);
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@ -56,13 +69,19 @@ NotchFilterLite::NotchFilterLite(ConfigurationInterface* configuration, std::str
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DLOG(INFO) << "dump_ is " << dump_;
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dump_filename_ = configuration->property(role + ".dump_filename", default_dump_file);
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p_c_factor = configuration->property(role + ".p_c_factor", default_p_c_factor);
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pfa = configuration->property(role + ".pfa", default_pfa);
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coeff_rate = configuration->property(role + ".coeff_rate", default_coeff_rate);
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length_ = configuration->property(role + ".length", default_length_);
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n_segments_est = configuration->property(role + ".segments_est", default_n_segments_est);
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n_segments_reset = configuration->property(role + ".segments_reset", default_n_segments_reset);
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int n_segments_coeff = (int) ((samp_freq / coeff_rate) / ((float) length_));
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n_segments_coeff = std::max(1, n_segments_coeff);
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if (item_type_.compare("gr_complex") == 0)
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{
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item_size_ = sizeof(gr_complex);
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notch_filter_lite_ = make_notch_filter_lite(p_c_factor);
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notch_filter_lite_ = make_notch_filter_lite(p_c_factor, pfa, length_, n_segments_est, n_segments_reset, n_segments_coeff);
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DLOG(INFO) << "Item size " << item_size_;
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DLOG(INFO) << "input filter(" << notch_filter_lite_->unique_id() << ")";
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}
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else
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{
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@ -43,12 +43,12 @@
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using google::LogMessage;
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notch_sptr make_notch_filter(float pfa, float p_c_factor,
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int length_)
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int length_, int n_segments_est, int n_segments_reset)
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{
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return notch_sptr(new Notch(pfa, p_c_factor, length_));
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return notch_sptr(new Notch(pfa, p_c_factor, length_, n_segments_est, n_segments_reset));
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}
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Notch::Notch(float pfa, float p_c_factor, int length_) : gr::block("Notch",
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Notch::Notch(float pfa, float p_c_factor, int length_, int n_segments_est, int n_segments_reset) : gr::block("Notch",
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gr::io_signature::make (1, 1, sizeof(gr_complex)),
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gr::io_signature::make (1, 1, sizeof(gr_complex)))
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{
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@ -63,8 +63,8 @@ Notch::Notch(float pfa, float p_c_factor, int length_) : gr::block("Notch",
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filter_state_ = false; //Initial state of the filter
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n_deg_fred = 2 * length_; //Number of dregrees of freedom
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n_segments = 0;
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n_segments_est = 8; // Set the number of segments for noise power estimation
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n_segments_reset = 10000; // Set the period (in segments) when the noise power is estimated
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this->n_segments_est = n_segments_est; // Set the number of segments for noise power estimation
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this->n_segments_reset = n_segments_reset; // Set the period (in segments) when the noise power is estimated
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z_0 = gr_complex(0 , 0);
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boost::math::chi_squared_distribution<float> my_dist_(n_deg_fred);
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thres_ = boost::math::quantile(boost::math::complement(my_dist_, pfa));
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@ -39,7 +39,7 @@ class Notch;
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typedef boost::shared_ptr<Notch> notch_sptr;
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notch_sptr make_notch_filter(float pfa, float p_c_factor,
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int length_);
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int length_, int n_segments_est, int n_segments_reset);
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/*!
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* \brief This class implements a real-time software-defined multi state notch filter
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@ -67,7 +67,7 @@ private:
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public:
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Notch(float pfa, float p_c_factor, int length_);
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Notch(float pfa, float p_c_factor, int length_, int n_segments_est, int n_segments_reset);
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~Notch();
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@ -37,15 +37,17 @@
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#include <volk/volk.h>
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#include <iostream>
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#include <glog/logging.h>
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#include <boost/math/distributions/chi_squared.hpp>
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#include <armadillo>
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using google::LogMessage;
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notch_lite_sptr make_notch_filter_lite(float p_c_factor)
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notch_lite_sptr make_notch_filter_lite(float p_c_factor, float pfa, int length_, int n_segments_est, int n_segments_reset, int n_segments_coeff)
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{
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return notch_lite_sptr(new NotchLite(p_c_factor));
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return notch_lite_sptr(new NotchLite(p_c_factor, pfa, length_, n_segments_est, n_segments_reset, n_segments_coeff));
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}
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NotchLite::NotchLite(float p_c_factor) : gr::block("NotchLite",
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NotchLite::NotchLite(float p_c_factor, float pfa, int length_, int n_segments_est, int n_segments_reset, int n_segments_coeff) : gr::block("NotchLite",
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gr::io_signature::make (1, 1, sizeof(gr_complex)),
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gr::io_signature::make (1, 1, sizeof(gr_complex)))
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{
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@ -53,28 +55,97 @@ NotchLite::NotchLite(float p_c_factor) : gr::block("NotchLite",
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set_alignment(std::max(1, alignment_multiple));
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set_history(2);
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this->p_c_factor = gr_complex(p_c_factor , 0);
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this->n_segments_est = n_segments_est;
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this->n_segments_reset = n_segments_reset;
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this->n_segments_coeff_reset = n_segments_coeff;
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this->n_segments_coeff = 0;
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this->length_ = length_;
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set_output_multiple(length_);
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this->pfa = pfa;
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n_segments = 0;
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n_deg_fred = 2 * length_;
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noise_pow_est = 0.0;
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filter_state_ = false;
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z_0 = gr_complex(0 , 0);
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last_out = gr_complex(0,0);
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last_out = gr_complex(0, 0);
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boost::math::chi_squared_distribution<float> my_dist_(n_deg_fred);
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thres_ = boost::math::quantile(boost::math::complement(my_dist_, pfa));
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c_samples = gr_complex(0, 0);
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angle_ = 0.0;
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power_spect = static_cast<float *>(volk_malloc(length_ * sizeof(float), volk_get_alignment()));
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}
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NotchLite::~NotchLite()
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{
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volk_free(power_spect);
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}
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int NotchLite::general_work(int noutput_items __attribute__((unused)), gr_vector_int &ninput_items __attribute__((unused)),
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gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)
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{
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int index_out = 0;
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float sig2dB = 0.0;
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float sig2lin = 0.0;
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lv_32fc_t dot_prod_;
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gr_complex* in = (gr_complex *) input_items[0];
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gr_complex* out = (gr_complex *) output_items[0];
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c_samples = static_cast<gr_complex *>(volk_malloc(noutput_items * sizeof(gr_complex), volk_get_alignment()));
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angle_ = static_cast<float *>(volk_malloc(noutput_items * sizeof(float), volk_get_alignment()));
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volk_32fc_x2_multiply_conjugate_32fc(c_samples, (in + 1), in, noutput_items);
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volk_32fc_s32f_atan2_32f(angle_, c_samples, ((float)1.0), noutput_items);
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for (int aux = 0; aux < noutput_items; aux++)
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in++;
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arma::cx_fvec signal_segment;
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arma::cx_fvec signal_segment_fft;
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while((index_out + length_) < noutput_items)
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{
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z_0 = std::exp(gr_complex(0,1) * (*(angle_ + aux)));
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*(out + aux) = *(in + aux + 1) - z_0 * (*(in + aux)) + p_c_factor * z_0 * last_out;
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last_out = *(out + aux);
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if((n_segments < n_segments_est) && (filter_state_ == false))
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{
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signal_segment = arma::cx_fvec(in, length_, false, false);
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signal_segment_fft = arma::fft(signal_segment);
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volk_32fc_s32f_power_spectrum_32f(power_spect, signal_segment_fft.memptr(), 1.0, length_);
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volk_32f_s32f_calc_spectral_noise_floor_32f(&sig2dB, power_spect, 15.0, length_);
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sig2lin = std::pow(10.0, (sig2dB / 10.0)) / ((float) n_deg_fred);
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noise_pow_est = (((float) n_segments) * noise_pow_est + sig2lin) / ((float)(n_segments + 1));
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memcpy(out, in, sizeof(gr_complex) * length_);
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}
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else
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{
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volk_32fc_x2_conjugate_dot_prod_32fc(&dot_prod_, in, in, length_);
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if( (lv_creal(dot_prod_) / noise_pow_est) > thres_)
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{
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if(filter_state_ == false)
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{
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filter_state_ = true;
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last_out = gr_complex(0,0);
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n_segments_coeff = 0;
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}
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if(n_segments_coeff == 0)
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{
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volk_32fc_x2_multiply_conjugate_32fc(&c_samples, in, (in - 1), 1);
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volk_32fc_s32f_atan2_32f(&angle_, &c_samples, ((float)1.0), 1);
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z_0 = std::exp(gr_complex(0,1) * angle_);
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}
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for(int aux = 0; aux < length_; aux++)
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{
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*(out + aux) = *(in + aux) - z_0 * (*(in + aux - 1)) + p_c_factor * z_0 * last_out;
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last_out = *(out + aux);
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}
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n_segments_coeff++;
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n_segments_coeff = n_segments_coeff % n_segments_coeff_reset;
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}
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else
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{
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if (n_segments > n_segments_reset)
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{
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n_segments = 0;
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}
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filter_state_ = false;
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memcpy(out, in, sizeof(gr_complex) * length_);
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}
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}
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index_out += length_;
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n_segments++;
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in += length_;
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out += length_;
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}
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volk_free(c_samples);
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volk_free(angle_);
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consume_each(noutput_items);
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return noutput_items;
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consume_each(index_out);
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return index_out;
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}
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@ -38,7 +38,7 @@ class NotchLite;
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typedef boost::shared_ptr<NotchLite> notch_lite_sptr;
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notch_lite_sptr make_notch_filter_lite(float p_c_factor);
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notch_lite_sptr make_notch_filter_lite(float p_c_factor, float pfa, int length_, int n_segments_est, int n_segments_reset, int n_segments_coeff);
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/*!
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* \brief This class implements a real-time software-defined single state notch filter
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@ -48,15 +48,29 @@ class NotchLite : public gr::block
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{
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private:
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int length_;
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int n_segments;
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int n_segments_est;
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int n_segments_reset;
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int n_segments_coeff_reset;
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int n_segments_coeff;
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int n_deg_fred;
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float pfa;
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float thres_;
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float noise_pow_est;
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bool filter_state_;
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gr_complex last_out;
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gr_complex z_0;
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gr_complex p_c_factor;
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gr_complex* c_samples;
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float* angle_;
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gr_complex c_samples;
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float angle_;
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float* power_spect;
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public:
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NotchLite(float p_c_factor);
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NotchLite(float p_c_factor, float pfa, int length_, int n_segments_est, int n_segments_reset, int n_segments_coeff);
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~NotchLite();
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int general_work (int noutput_items, gr_vector_int &ninput_items,
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gr_vector_const_void_star &input_items,
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