NFM mod: make pre-emphasis and CTCSS highpass filter optional so that digital modulation from file is possible

plugins/channeltx/modnfm/nfmmodgui.cpp

@@ -202,6 +202,12 @@ void NFMModGUI::on_afBW_valueChanged(int value)
 	applySettings();
 }
 
+void NFMModGUI::on_preEmphasis_toggled(bool checked)
+{
+    m_settings.m_preEmphasisOn = checked;
+    applySettings();
+}
+
 void NFMModGUI::on_fmDev_valueChanged(int value)
 {
 	ui->fmDevText->setText(QString("%1%2k").arg(QChar(0xB1, 0x00)).arg(value / 10.0, 0, 'f', 1));
@@ -352,6 +358,12 @@ void NFMModGUI::on_dcsPositive_toggled(bool checked)
     applySettings();
 }
 
+void NFMModGUI::on_bpf_toggled(bool checked)
+{
+    m_settings.m_bpfOn = checked;
+    applySettings();
+}
+
 void NFMModGUI::configureFileName()
 {
     qDebug() << "FileSourceGui::configureFileName: " << m_fileName.toStdString().c_str();
@@ -546,6 +558,7 @@ void NFMModGUI::displaySettings()
 
     ui->afBWText->setText(QString("%1k").arg(m_settings.m_afBandwidth / 1000.0, 0, 'f', 1));
     ui->afBW->setValue(m_settings.m_afBandwidth / 100.0);
+    ui->preEmphasis->setChecked(m_settings.m_preEmphasisOn);
 
     ui->fmDevText->setText(QString("%1%2k").arg(QChar(0xB1, 0x00)).arg(m_settings.m_fmDeviation / 2000.0, 0, 'f', 1));
     ui->fmDev->setValue(m_settings.m_fmDeviation / 200.0);
@@ -567,6 +580,7 @@ void NFMModGUI::displaySettings()
     ui->dcsOn->setEnabled(!m_settings.m_ctcssOn);
     ui->dcsCode->setText(tr("%1").arg(m_settings.m_dcsCode, 3, 8, QLatin1Char('0')));
     ui->dcsPositive->setChecked(m_settings.m_dcsPositive);
+    ui->bpf->setChecked(m_settings.m_bpfOn);
 
     ui->channelMute->setChecked(m_settings.m_channelMute);
     ui->playLoop->setChecked(m_settings.m_playLoop);
@@ -707,6 +721,7 @@ void NFMModGUI::makeUIConnections()
     QObject::connect(ui->channelSpacingApply, &QPushButton::clicked, this, &NFMModGUI::on_channelSpacingApply_clicked);
     QObject::connect(ui->rfBW, &QSlider::valueChanged, this, &NFMModGUI::on_rfBW_valueChanged);
     QObject::connect(ui->afBW, &QSlider::valueChanged, this, &NFMModGUI::on_afBW_valueChanged);
+    QObject::connect(ui->preEmphasis, &QCheckBox::toggled, this, &NFMModGUI::on_preEmphasis_toggled);
     QObject::connect(ui->fmDev, &QSlider::valueChanged, this, &NFMModGUI::on_fmDev_valueChanged);
     QObject::connect(ui->toneFrequency, &QDial::valueChanged, this, &NFMModGUI::on_toneFrequency_valueChanged);
     QObject::connect(ui->volume, &QDial::valueChanged, this, &NFMModGUI::on_volume_valueChanged);
@@ -723,6 +738,7 @@ void NFMModGUI::makeUIConnections()
     QObject::connect(ui->dcsOn, &QCheckBox::toggled, this, &NFMModGUI::on_dcsOn_toggled);
     QObject::connect(ui->dcsCode, &QLineEdit::editingFinished, this, &NFMModGUI::on_dcsCode_editingFinished);
     QObject::connect(ui->dcsPositive, &QCheckBox::toggled, this, &NFMModGUI::on_dcsPositive_toggled);
+    QObject::connect(ui->bpf, &QCheckBox::toggled, this, &NFMModGUI::on_bpf_toggled);
     QObject::connect(ui->feedbackEnable, &QToolButton::toggled, this, &NFMModGUI::on_feedbackEnable_toggled);
     QObject::connect(ui->feedbackVolume, &QDial::valueChanged, this, &NFMModGUI::on_feedbackVolume_valueChanged);
 }

plugins/channeltx/modnfm/nfmmodgui.h

@@ -114,6 +114,7 @@ private slots:
     void on_channelSpacingApply_clicked();
     void on_rfBW_valueChanged(int value);
     void on_afBW_valueChanged(int value);
+    void on_preEmphasis_toggled(bool checked);
     void on_fmDev_valueChanged(int value);
     void on_toneFrequency_valueChanged(int value);
     void on_volume_valueChanged(int value);
@@ -132,6 +133,7 @@ private slots:
     void on_dcsOn_toggled(bool checked);
     void on_dcsCode_editingFinished();
     void on_dcsPositive_toggled(bool checked);
+    void on_bpf_toggled(bool checked);
 
     void on_feedbackEnable_toggled(bool checked);
     void on_feedbackVolume_valueChanged(int value);

plugins/channeltx/modnfm/nfmmodgui.ui

@@ -279,6 +279,42 @@
         </property>
        </widget>
       </item>
+      <item>
+       <widget class="ButtonSwitch" name="preEmphasis">
+        <property name="minimumSize">
+         <size>
+          <width>24</width>
+          <height>0</height>
+         </size>
+        </property>
+        <property name="toolTip">
+         <string>Pre-emphasis (120us) on/off</string>
+        </property>
+        <property name="text">
+         <string>P</string>
+        </property>
+       </widget>
+      </item>
+      <item>
+       <widget class="ButtonSwitch" name="bpf">
+        <property name="maximumSize">
+         <size>
+          <width>24</width>
+          <height>16777215</height>
+         </size>
+        </property>
+        <property name="toolTip">
+         <string>Audio high pass filter for CTCSS on/off</string>
+        </property>
+        <property name="text">
+         <string/>
+        </property>
+        <property name="icon">
+         <iconset resource="../../../sdrgui/resources/res.qrc">
+          <normaloff>:/filter_highpass.png</normaloff>:/filter_highpass.png</iconset>
+        </property>
+       </widget>
+      </item>
      </layout>
     </item>
     <item>

plugins/channeltx/modnfm/nfmmodsettings.cpp

@@ -66,6 +66,8 @@ void NFMModSettings::resetToDefaults()
     m_dcsOn = false;
     m_dcsCode = 0023;
     m_dcsPositive = false;
+    m_preEmphasisOn = true;
+    m_bpfOn = true;
     m_rgbColor = QColor(255, 0, 0).rgb();
     m_title = "NFM Modulator";
     m_modAFInput = NFMModInputAF::NFMModInputNone;
@@ -98,15 +100,16 @@ QByteArray NFMModSettings::serialize() const
     if (m_cwKeyerGUI) {
         s.writeBlob(8, m_cwKeyerGUI->serialize());
     } else { // standalone operation with presets
-        s.writeBlob(6, m_cwKeyerSettings.serialize());
+        s.writeBlob(8, m_cwKeyerSettings.serialize());
     }
 
+    s.writeBool(9, m_ctcssOn);
+    s.writeS32(10, m_ctcssIndex);
+
     if (m_channelMarker) {
         s.writeBlob(11, m_channelMarker->serialize());
     }
 
-    s.writeBool(9, m_ctcssOn);
-    s.writeS32(10, m_ctcssIndex);
     s.writeString(12, m_title);
     s.writeS32(13, (int) m_modAFInput);
     s.writeString(14, m_audioDeviceName);
@@ -130,6 +133,8 @@ QByteArray NFMModSettings::serialize() const
     s.writeS32(28, m_workspaceIndex);
     s.writeBlob(29, m_geometryBytes);
     s.writeBool(30, m_hidden);
+    s.writeBool(31, m_preEmphasisOn);
+    s.writeBool(32, m_bpfOn);
 
     return s.final();
 }
@@ -217,6 +222,8 @@ bool NFMModSettings::deserialize(const QByteArray& data)
         d.readS32(28, &m_workspaceIndex, 0);
         d.readBlob(29, &m_geometryBytes);
         d.readBool(30, &m_hidden, false);
+        d.readBool(31, &m_preEmphasisOn, true);
+        d.readBool(32, &m_bpfOn, true);
 
         return true;
     }

plugins/channeltx/modnfm/nfmmodsettings.h

@@ -54,6 +54,8 @@ struct NFMModSettings
     bool m_dcsOn;
     int m_dcsCode;
     bool m_dcsPositive;
+    bool m_preEmphasisOn;
+    bool m_bpfOn;
     quint32 m_rgbColor;
     QString m_title;
     NFMModInputAF m_modAFInput;

plugins/channeltx/modnfm/nfmmodsource.cpp

@@ -144,7 +144,12 @@ void NFMModSource::modulateSample()
 	Real t0, t1, t;
 
     pullAF(t0);
-    m_preemphasisFilter.process(t0, t);
+
+    if (m_settings.m_preEmphasisOn) {
+        m_preemphasisFilter.process(t0, t);
+    } else {
+        t = t0;
+    }
 
     if (m_settings.m_feedbackAudioEnable) {
         pushFeedback(t * m_settings.m_feedbackVolumeFactor * 16384.0f);
@@ -156,8 +161,10 @@ void NFMModSource::modulateSample()
         t1 = (0.85f * m_bandpass.filter(t) + 0.15f * 0.625f * m_ctcssNco.next()) * 1.2f;
     } else if (m_settings.m_dcsOn) {
         t1 = (0.9f * m_bandpass.filter(t) + 0.1f * 0.625f * m_dcsMod.next()) * 1.2f;
-    } else {
+    } else if (m_settings.m_bpfOn) {
         t1 = m_bandpass.filter(t) * 1.2f;
+    } else {
+        t1 = m_lowpass.filter(t) * 1.2f;
     }
 
     m_modPhasor += (m_settings.m_fmDeviation / (float) m_audioSampleRate) * t1;
@@ -350,7 +357,7 @@ void NFMModSource::applyAudioSampleRate(int sampleRate)
     m_interpolatorConsumed = false;
     m_interpolatorDistance = (Real) sampleRate / (Real) m_channelSampleRate;
     m_interpolator.create(48, sampleRate, m_settings.m_rfBandwidth / 2.2, 3.0);
-    m_lowpass.create(301, sampleRate, 250.0);
+    m_lowpass.create(301, sampleRate, m_settings.m_afBandwidth);
     m_bandpass.create(301, sampleRate, 300.0, m_settings.m_afBandwidth);
     m_toneNco.setFreq(m_settings.m_toneFrequency, sampleRate);
     m_ctcssNco.setFreq(NFMModSettings::getCTCSSFreq(m_settings.m_ctcssIndex), sampleRate);