From 772a150136a30d70e4efde64a73010d29fb2637c Mon Sep 17 00:00:00 2001
From: f4exb <f4exb06@gmail.com>
Date: Mon, 26 Nov 2018 08:54:06 +0100
Subject: [PATCH] RTLSDR: implemented offset tuning

---
 plugins/samplesource/rtlsdr/rtlsdrgui.cpp     |  7 +++++++
 plugins/samplesource/rtlsdr/rtlsdrgui.h       |  1 +
 plugins/samplesource/rtlsdr/rtlsdrgui.ui      | 10 +++++++++
 plugins/samplesource/rtlsdr/rtlsdrinput.cpp   | 21 ++++++++++++++-----
 .../samplesource/rtlsdr/rtlsdrsettings.cpp    |  3 +++
 plugins/samplesource/rtlsdr/rtlsdrsettings.h  |  1 +
 6 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/plugins/samplesource/rtlsdr/rtlsdrgui.cpp b/plugins/samplesource/rtlsdr/rtlsdrgui.cpp
index 381a2b053..92cd317f7 100644
--- a/plugins/samplesource/rtlsdr/rtlsdrgui.cpp
+++ b/plugins/samplesource/rtlsdr/rtlsdrgui.cpp
@@ -261,6 +261,7 @@ void RTLSDRGui::displaySettings()
 	ui->checkBox->setChecked(m_settings.m_noModMode);
 	ui->agc->setChecked(m_settings.m_agc);
 	ui->lowSampleRate->setChecked(m_settings.m_lowSampleRate);
+	ui->offsetTuning->setChecked(m_settings.m_offsetTuning);
 }
 
 void RTLSDRGui::sendSettings()
@@ -441,6 +442,12 @@ void RTLSDRGui::on_sampleRate_changed(quint64 value)
     sendSettings();
 }
 
+void RTLSDRGui::on_offsetTuning_toggled(bool checked)
+{
+    m_settings.m_offsetTuning = checked;
+    sendSettings();
+}
+
 void RTLSDRGui::on_rfBW_changed(quint64 value)
 {
     m_settings.m_rfBandwidth = value * 1000;
diff --git a/plugins/samplesource/rtlsdr/rtlsdrgui.h b/plugins/samplesource/rtlsdr/rtlsdrgui.h
index f2c838618..69e010f68 100644
--- a/plugins/samplesource/rtlsdr/rtlsdrgui.h
+++ b/plugins/samplesource/rtlsdr/rtlsdrgui.h
@@ -78,6 +78,7 @@ private slots:
     void handleInputMessages();
 	void on_centerFrequency_changed(quint64 value);
 	void on_sampleRate_changed(quint64 value);
+	void on_offsetTuning_toggled(bool checked);
     void on_rfBW_changed(quint64 value);
 	void on_lowSampleRate_toggled(bool checked);
 	void on_dcOffset_toggled(bool checked);
diff --git a/plugins/samplesource/rtlsdr/rtlsdrgui.ui b/plugins/samplesource/rtlsdr/rtlsdrgui.ui
index 79b0dd127..0549f25e6 100644
--- a/plugins/samplesource/rtlsdr/rtlsdrgui.ui
+++ b/plugins/samplesource/rtlsdr/rtlsdrgui.ui
@@ -493,6 +493,16 @@
        </property>
       </spacer>
      </item>
+     <item>
+      <widget class="QCheckBox" name="offsetTuning">
+       <property name="toolTip">
+        <string>Offset tuning</string>
+       </property>
+       <property name="text">
+        <string>Ofs</string>
+       </property>
+      </widget>
+     </item>
      <item>
       <widget class="QLabel" name="rfBWabel">
        <property name="text">
diff --git a/plugins/samplesource/rtlsdr/rtlsdrinput.cpp b/plugins/samplesource/rtlsdr/rtlsdrinput.cpp
index f78765cca..394096e59 100644
--- a/plugins/samplesource/rtlsdr/rtlsdrinput.cpp
+++ b/plugins/samplesource/rtlsdr/rtlsdrinput.cpp
@@ -507,17 +507,28 @@ bool RTLSDRInput::applySettings(const RTLSDRSettings& settings, bool force)
 
         if (m_dev != 0)
         {
-            if (rtlsdr_set_tuner_bandwidth( m_dev, m_settings.m_rfBandwidth) != 0)
-            {
+            if (rtlsdr_set_tuner_bandwidth( m_dev, m_settings.m_rfBandwidth) != 0) {
                 qCritical("RTLSDRInput::applySettings: could not set RF bandwidth to %u", m_settings.m_rfBandwidth);
-            }
-            else
-            {
+            } else {
                 qDebug() << "RTLSDRInput::applySettings: set RF bandwidth to " << m_settings.m_rfBandwidth;
             }
         }
     }
 
+    if ((m_settings.m_offsetTuning != settings.m_offsetTuning) || force)
+    {
+        m_settings.m_offsetTuning = settings.m_offsetTuning;
+
+        if (m_dev != 0)
+        {
+            if (rtlsdr_set_offset_tuning(m_dev, m_settings.m_offsetTuning ? 0 : 1) != 0) {
+                qCritical("RTLSDRInput::applySettings: could not set offset tuning to %s", m_settings.m_offsetTuning ? "on" : "off");
+            } else {
+                qDebug("RTLSDRInput::applySettings: offset tuning set to %s", m_settings.m_offsetTuning ? "on" : "off");
+            }
+        }
+    }
+
     if (forwardChange)
     {
         int sampleRate = m_settings.m_devSampleRate/(1<<m_settings.m_log2Decim);
diff --git a/plugins/samplesource/rtlsdr/rtlsdrsettings.cpp b/plugins/samplesource/rtlsdr/rtlsdrsettings.cpp
index 6b5fd6ead..95494b820 100644
--- a/plugins/samplesource/rtlsdr/rtlsdrsettings.cpp
+++ b/plugins/samplesource/rtlsdr/rtlsdrsettings.cpp
@@ -40,6 +40,7 @@ void RTLSDRSettings::resetToDefaults()
 	m_transverterDeltaFrequency = 0;
 	m_rfBandwidth = 2500 * 1000; // Hz
 	m_fileRecordName = "";
+	m_offsetTuning = false;
 }
 
 QByteArray RTLSDRSettings::serialize() const
@@ -59,6 +60,7 @@ QByteArray RTLSDRSettings::serialize() const
     s.writeBool(12, m_transverterMode);
     s.writeS64(13, m_transverterDeltaFrequency);
     s.writeU32(14, m_rfBandwidth);
+    s.writeBool(15, m_offsetTuning);
 
 	return s.final();
 }
@@ -91,6 +93,7 @@ bool RTLSDRSettings::deserialize(const QByteArray& data)
         d.readBool(12, &m_transverterMode, false);
         d.readS64(13, &m_transverterDeltaFrequency, 0);
         d.readU32(4, &m_rfBandwidth, 2500 * 1000);
+        d.readBool(15, &m_offsetTuning, false);
 
 		return true;
 	}
diff --git a/plugins/samplesource/rtlsdr/rtlsdrsettings.h b/plugins/samplesource/rtlsdr/rtlsdrsettings.h
index bf2ad2c60..e42b92616 100644
--- a/plugins/samplesource/rtlsdr/rtlsdrsettings.h
+++ b/plugins/samplesource/rtlsdr/rtlsdrsettings.h
@@ -41,6 +41,7 @@ struct RTLSDRSettings {
 	qint64 m_transverterDeltaFrequency;
 	quint32 m_rfBandwidth; //!< RF filter bandwidth in Hz
 	QString m_fileRecordName;
+	bool m_offsetTuning;
 
 	RTLSDRSettings();
 	void resetToDefaults();