Add lowpass filtering

Lowpass filtering implementation in freq_xlating

src/algorithms/input_filter/adapters/freq_xlating_fir_filter.cc

@@ -32,6 +32,7 @@
 #include <boost/lexical_cast.hpp>
 #include <gnuradio/blocks/file_sink.h>
 #include <gnuradio/filter/pm_remez.h>
+#include <gnuradio/filter/firdes.h>
 #include <glog/logging.h>
 #include <volk/volk.h>
 #include "configuration_interface.h"
@@ -343,8 +344,8 @@ void FreqXlatingFirFilter::init()
     std::string default_output_item_type = "gr_complex";
     std::string default_taps_item_type = "float";
     std::string default_dump_filename = "../data/input_filter.dat";
-    double default_intermediate_freq = 0;
+    double default_intermediate_freq = 0.0;
-    double default_sampling_freq = 4000000;
+    double default_sampling_freq = 4000000.0;
     int default_number_of_taps = 6;
     unsigned int default_number_of_bands = 2;
     std::vector<double> default_bands = { 0.0, 0.4, 0.6, 1.0 };
@@ -364,46 +365,54 @@ void FreqXlatingFirFilter::init()
     sampling_freq_ = config_->property(role_ + ".sampling_frequency", default_sampling_freq);
     int number_of_taps = config_->property(role_ + ".number_of_taps", default_number_of_taps);
     unsigned int number_of_bands = config_->property(role_ + ".number_of_bands", default_number_of_bands);
-
-    std::vector<double> bands;
-    std::vector<double> ampl;
-    std::vector<double> error_w;
-    std::string option;
-    double option_value;
-
-    for (unsigned int i = 0; i < number_of_bands; i++)
-        {
-            option = ".band" + boost::lexical_cast<std::string>(i + 1) + "_begin";
-            option_value = config_->property(role_ + option, default_bands[i]);
-            bands.push_back(option_value);
-
-            option = ".band" + boost::lexical_cast<std::string>(i + 1) + "_end";
-            option_value = config_->property(role_ + option, default_bands[i]);
-            bands.push_back(option_value);
-
-            option = ".ampl" + boost::lexical_cast<std::string>(i + 1) + "_begin";
-            option_value = config_->property(role_ + option, default_bands[i]);
-            ampl.push_back(option_value);
-
-            option = ".ampl" + boost::lexical_cast<std::string>(i + 1) + "_end";
-            option_value = config_->property(role_ + option, default_bands[i]);
-            ampl.push_back(option_value);
-
-            option = ".band" + boost::lexical_cast<std::string>(i + 1) + "_error";
-            option_value = config_->property(role_ + option, default_bands[i]);
-            error_w.push_back(option_value);
-        }
-
     std::string filter_type = config_->property(role_ + ".filter_type", default_filter_type);
-    int grid_density = config_->property(role_ + ".grid_density", default_grid_density);
 
-    std::vector<double> taps_d = gr::filter::pm_remez(number_of_taps - 1, bands, ampl,
+    if(filter_type.compare("lowpass") != 0)
-            error_w, filter_type, grid_density);
-
-    taps_.reserve(taps_d.size());
-    for (std::vector<double>::iterator it = taps_d.begin(); it != taps_d.end(); it++)
         {
-            taps_.push_back(float(*it));
+    	    std::vector<double> taps_d;
-            //std::cout<<"TAP="<<float(*it)<<std::endl;
+    	    std::vector<double> bands;
+            std::vector<double> ampl;
+            std::vector<double> error_w;
+            std::string option;
+            double option_value;
+
+            for (unsigned int i = 0; i < number_of_bands; i++)
+                {
+                    option = ".band" + boost::lexical_cast<std::string>(i + 1) + "_begin";
+                    option_value = config_->property(role_ + option, default_bands[i]);
+                    bands.push_back(option_value);
+
+                    option = ".band" + boost::lexical_cast<std::string>(i + 1) + "_end";
+                    option_value = config_->property(role_ + option, default_bands[i]);
+                    bands.push_back(option_value);
+
+                    option = ".ampl" + boost::lexical_cast<std::string>(i + 1) + "_begin";
+                    option_value = config_->property(role_ + option, default_bands[i]);
+                    ampl.push_back(option_value);
+
+                    option = ".ampl" + boost::lexical_cast<std::string>(i + 1) + "_end";
+                    option_value = config_->property(role_ + option, default_bands[i]);
+                    ampl.push_back(option_value);
+
+                    option = ".band" + boost::lexical_cast<std::string>(i + 1) + "_error";
+                    option_value = config_->property(role_ + option, default_bands[i]);
+                    error_w.push_back(option_value);
+                }
+
+            int grid_density = config_->property(role_ + ".grid_density", default_grid_density);
+            taps_d = gr::filter::pm_remez(number_of_taps - 1, bands, ampl, error_w, filter_type, grid_density);
+            taps_.reserve(taps_d.size());
+            for (std::vector<double>::iterator it = taps_d.begin(); it != taps_d.end(); it++)
+                {
+                    taps_.push_back(static_cast<float>(*it));
+                }
         }
+    else
+        {
+    	    double default_bw = 2000000.0;
+    	    double bw_ = config_->property(role_ + ".bw", default_bw);
+    	    double default_tw = bw_ / 20.0;
+    	    double tw_ = config_->property(role_ + ".tw", default_tw);
+    	    taps_ = gr::filter::firdes::low_pass(1.0, sampling_freq_, bw_ / 2.0, tw_);
+    	}
 }

src/algorithms/input_filter/adapters/pulse_blanking_filter.cc

@@ -28,13 +28,13 @@
  * -------------------------------------------------------------------------
  */
 
-#include "pulse_blanking_filter.h"
 #include <boost/lexical_cast.hpp>
 #include <vector>
+#include <cmath>
 #include <glog/logging.h>
 #include <gnuradio/filter/firdes.h>
 #include "configuration_interface.h"
-#include <vector>
+#include "pulse_blanking_filter.h"
 
 using google::LogMessage;
 
@@ -74,13 +74,13 @@ PulseBlankingFilter::PulseBlankingFilter(ConfigurationInterface* configuration,
             item_size = sizeof(gr_complex); //avoids uninitialization
             input_size_ = sizeof(gr_complex); //avoids uninitialization
         }
-    float default_if = 0.0;
+    double default_if = 0.0;
-    float if_ = config_->property(role_ + ".if", default_if);
+    double if_ = config_->property(role_ + ".if", default_if);
-    if (if_ > 0.0)
+    if (std::abs(if_) > 1.0)
         {
             double default_bw = 2000000.0;
             double bw_ = config_->property(role_ + ".bw", default_bw);
-            double default_tw = bw_ / 15.0;
+            double default_tw = bw_ / 20.0;
             double tw_ = config_->property(role_ + ".tw", default_tw);
             const std::vector<float> taps = gr::filter::firdes::low_pass(1.0, config_->property("SignalSource.sampling_frequency", 2000000.0), bw_ / 2.0, tw_);
             freq_xlating_ = gr::filter::freq_xlating_fir_filter_ccf::make(1, taps, if_, config_->property("SignalSource.sampling_frequency", 2000000.0));
@@ -108,7 +108,7 @@ void PulseBlankingFilter::connect(gr::top_block_sptr top_block)
                 {
                     top_block->connect(pulse_blanking_cc_, 0, file_sink_, 0);
                 }
-            if (config_->property(role_ + ".if", 0.0) > 0.0)
+            if (std::abs(config_->property(role_ + ".if", 0.0)) > 1.0)
                 {
                     top_block->connect(freq_xlating_, 0, pulse_blanking_cc_, 0);
                 }
@@ -130,7 +130,7 @@ void PulseBlankingFilter::disconnect(gr::top_block_sptr top_block)
                 {
                     top_block->disconnect(pulse_blanking_cc_, 0, file_sink_, 0);
                 }
-            if (config_->property(role_ + ".if", 0.0) > 0.0)
+            if (std::abs(config_->property(role_ + ".if", 0.0)) > 1.0)
                 {
                     top_block->disconnect(freq_xlating_, 0, pulse_blanking_cc_, 0);
                 }
@@ -146,7 +146,7 @@ gr::basic_block_sptr PulseBlankingFilter::get_left_block()
 {
     if (input_item_type_.compare("gr_complex") == 0)
         {
-            if (config_->property(role_ + ".if", 0.0) > 0.0)
+            if (std::abs(config_->property(role_ + ".if", 0.0)) > 1.0)
                 {
                     return freq_xlating_;
                 }

src/algorithms/input_filter/adapters/pulse_blanking_filter.h

@@ -33,7 +33,6 @@
 #define GNSS_SDR_PULSE_BLANKING_FILTER_H_
 
 #include <string>
-#include <vector>
 #include <gnuradio/blocks/file_sink.h>
 #include <gnuradio/filter/freq_xlating_fir_filter_ccf.h>
 #include "gnss_block_interface.h"