Channel analyzer NG: implemented optional RRC filter

plugins/channelrx/chanalyzerng/chanalyzerng.cpp

@@ -52,6 +52,7 @@ ChannelAnalyzerNG::ChannelAnalyzerNG(DeviceSourceAPI *deviceAPI) :
 	m_inputFrequencyOffset = 0;
 	SSBFilter = new fftfilt(m_settings.m_lowCutoff / m_inputSampleRate, m_settings.m_bandwidth / m_inputSampleRate, ssbFftLen);
 	DSBFilter = new fftfilt(m_settings.m_bandwidth / m_inputSampleRate, 2*ssbFftLen);
+	RRCFilter = new fftfilt(m_settings.m_bandwidth / m_inputSampleRate, 2*ssbFftLen);
 	m_corr = new fftcorr(8*ssbFftLen); // 8k for 4k effective samples
 	m_pll.computeCoefficients(0.002f, 0.5f, 10.0f); // bandwidth, damping factor, loop gain
 
@@ -72,6 +73,7 @@ ChannelAnalyzerNG::~ChannelAnalyzerNG()
     delete m_channelizer;
     delete SSBFilter;
     delete DSBFilter;
+    delete RRCFilter;
 }
 
 void ChannelAnalyzerNG::configure(MessageQueue* messageQueue,
@@ -129,10 +131,17 @@ void ChannelAnalyzerNG::processOneSample(Complex& c, fftfilt::cmplx *sideband)
     int n_out;
     int decim = 1<<m_settings.m_spanLog2;
 
-    if (m_settings.m_ssb) {
+    if (m_settings.m_ssb)
+    {
         n_out = SSBFilter->runSSB(c, &sideband, m_usb);
-    } else {
+    }
-        n_out = DSBFilter->runDSB(c, &sideband);
+    else
+    {
+        if (m_settings.m_rrc) {
+            n_out = RRCFilter->runFilt(c, &sideband);
+        } else {
+            n_out = DSBFilter->runDSB(c, &sideband);
+        }
     }
 
     for (int i = 0; i < n_out; i++)
@@ -293,6 +302,7 @@ void ChannelAnalyzerNG::setFilters(int sampleRate, float bandwidth, float lowCut
 
     SSBFilter->create_filter(lowCutoff / sampleRate, bandwidth / sampleRate);
     DSBFilter->create_dsb_filter(bandwidth / sampleRate);
+    RRCFilter->create_rrc_filter(bandwidth / sampleRate, m_settings.m_rrcRolloff / 100.0);
 }
 
 void ChannelAnalyzerNG::applySettings(const ChannelAnalyzerNGSettings& settings, bool force)
@@ -300,6 +310,8 @@ void ChannelAnalyzerNG::applySettings(const ChannelAnalyzerNGSettings& settings,
     qDebug() << "ChannelAnalyzerNG::applySettings:"
             << " m_downSample: " << settings.m_downSample
             << " m_downSampleRate: " << settings.m_downSampleRate
+            << " m_rcc: " << settings.m_rrc
+            << " m_rrcRolloff: " << settings.m_rrcRolloff / 100.0
             << " m_bandwidth: " << settings.m_bandwidth
             << " m_lowCutoff: " << settings.m_lowCutoff
             << " m_spanLog2: " << settings.m_spanLog2
@@ -338,6 +350,14 @@ void ChannelAnalyzerNG::applySettings(const ChannelAnalyzerNGSettings& settings,
         m_settingsMutex.unlock();
     }
 
+    if ((settings.m_rrcRolloff != m_settings.m_rrcRolloff) || force)
+    {
+        float sampleRate = settings.m_downSample ? (float) settings.m_downSampleRate : (float) m_inputSampleRate;
+        m_settingsMutex.lock();
+        RRCFilter->create_rrc_filter(settings.m_bandwidth / sampleRate, settings.m_rrcRolloff / 100.0);
+        m_settingsMutex.unlock();
+    }
+
     if ((settings.m_spanLog2 != m_settings.m_spanLog2) || force)
     {
         int sampleRate = (settings.m_downSample ? settings.m_downSampleRate : m_inputSampleRate) / (1<<m_settings.m_spanLog2);

plugins/channelrx/chanalyzerng/chanalyzerng.h

@@ -231,6 +231,7 @@ private:
 
 	fftfilt* SSBFilter;
 	fftfilt* DSBFilter;
+	fftfilt* RRCFilter;
 	fftcorr* m_corr;
 
 	BasebandSampleSink* m_sampleSink;

plugins/channelrx/chanalyzerng/chanalyzernggui.cpp

@@ -114,6 +114,9 @@ void ChannelAnalyzerNGGUI::displaySettings()
     ui->spanLog2->setCurrentIndex(m_settings.m_spanLog2);
     displayPLLSettings();
     ui->signalSelect->setCurrentIndex((int) m_settings.m_inputType);
+    ui->rrcFilter->setChecked(m_settings.m_rrc);
+    QString rolloffStr = QString::number(m_settings.m_rrcRolloff/100.0, 'f', 2);
+    ui->rrcRolloffText->setText(rolloffStr);
 
     blockApplySettings(false);
 }
@@ -291,6 +294,20 @@ void ChannelAnalyzerNGGUI::on_deltaFrequency_changed(qint64 value)
     applySettings();
 }
 
+void ChannelAnalyzerNGGUI::on_rrcFilter_toggled(bool checked)
+{
+    m_settings.m_rrc = checked;
+    applySettings();
+}
+
+void ChannelAnalyzerNGGUI::on_rrcRolloff_valueChanged(int value)
+{
+    m_settings.m_rrcRolloff = value;
+    QString rolloffStr = QString::number(value/100.0, 'f', 2);
+    ui->rrcRolloffText->setText(rolloffStr);
+    applySettings();
+}
+
 void ChannelAnalyzerNGGUI::on_BW_valueChanged(int value __attribute__((unused)))
 {
     setFiltersUIBoundaries();

plugins/channelrx/chanalyzerng/chanalyzernggui.h

@@ -99,6 +99,8 @@ private slots:
     void on_pllPskOrder_currentIndexChanged(int index);
     void on_useRationalDownsampler_toggled(bool checked);
     void on_signalSelect_currentIndexChanged(int index);
+    void on_rrcFilter_toggled(bool checked);
+    void on_rrcRolloff_valueChanged(int value);
 	void on_BW_valueChanged(int value);
 	void on_lowCut_valueChanged(int value);
 	void on_spanLog2_currentIndexChanged(int index);

plugins/channelrx/chanalyzerng/chanalyzernggui.ui

@@ -419,6 +419,58 @@
     </item>
     <item>
      <layout class="QHBoxLayout" name="BWLayout">
+      <item>
+       <widget class="ButtonSwitch" name="rrcFilter">
+        <property name="toolTip">
+         <string>Toggle RRC filter</string>
+        </property>
+        <property name="text">
+         <string/>
+        </property>
+        <property name="icon">
+         <iconset resource="../../../sdrgui/resources/res.qrc">
+          <normaloff>:/dsb.png</normaloff>:/dsb.png</iconset>
+        </property>
+        <property name="checkable">
+         <bool>true</bool>
+        </property>
+       </widget>
+      </item>
+      <item>
+       <widget class="QDial" name="rrcRolloff">
+        <property name="maximumSize">
+         <size>
+          <width>24</width>
+          <height>24</height>
+         </size>
+        </property>
+        <property name="toolTip">
+         <string>Tune RRC filter rolloff factor</string>
+        </property>
+        <property name="minimum">
+         <number>10</number>
+        </property>
+        <property name="maximum">
+         <number>50</number>
+        </property>
+        <property name="pageStep">
+         <number>1</number>
+        </property>
+        <property name="value">
+         <number>30</number>
+        </property>
+       </widget>
+      </item>
+      <item>
+       <widget class="QLabel" name="rrcRolloffText">
+        <property name="toolTip">
+         <string>RRC filter rolloff factor value</string>
+        </property>
+        <property name="text">
+         <string>0.00</string>
+        </property>
+       </widget>
+      </item>
       <item>
        <widget class="QLabel" name="BWLabel">
         <property name="minimumSize">

plugins/channelrx/chanalyzerng/chanalyzerngsettings.cpp

@@ -40,6 +40,8 @@ void ChannelAnalyzerNGSettings::resetToDefaults()
     m_ssb = false;
     m_pll = false;
     m_fll = false;
+    m_rrc = false;
+    m_rrcRolloff = 30; // 0.3
     m_pllPskOrder = 1;
     m_inputType = InputSignal;
     m_rgbColor = QColor(128, 128, 128).rgb();
@@ -65,6 +67,8 @@ QByteArray ChannelAnalyzerNGSettings::serialize() const
     s.writeU32(13, m_pllPskOrder);
     s.writeS32(14, (int) m_inputType);
     s.writeString(15, m_title);
+    s.writeBool(16, m_rrc);
+    s.writeU32(17, m_rrcRolloff);
 
     return s.final();
 }
@@ -110,6 +114,8 @@ bool ChannelAnalyzerNGSettings::deserialize(const QByteArray& data)
         d.readS32(14, &tmp, 0);
         m_inputType = (InputType) tmp;
         d.readString(15, &m_title, "Channel Analyzer NG");
+        d.readBool(16, &m_rrc, false);
+        d.readU32(17, &m_rrcRolloff, 30);
 
         return true;
     }

plugins/channelrx/chanalyzerng/chanalyzerngsettings.h

@@ -39,6 +39,8 @@ struct ChannelAnalyzerNGSettings
     bool m_ssb;
     bool m_pll;
     bool m_fll;
+    bool m_rrc;
+    quint32 m_rrcRolloff; //!< in 100ths
     unsigned int m_pllPskOrder;
     InputType m_inputType;
     quint32 m_rgbColor;

sdrbase/dsp/fftfilt.h

@@ -69,7 +69,7 @@ protected:
 	{
         float x = i/(float)len; // normalize to [0..1]
         x = 0.5-fabs(x-0.5); // apply symmetry: now both halves overlap near 0
-        float tr = (fb*a)/2.0; // half the transition zone
+        float tr = fb*a; // half the transition zone
 
         if (x < fb-tr)
         {