PlutoSDR input: restore full range of FIR Rx gain

devices/plutosdr/deviceplutosdrbox.cpp

@@ -27,6 +27,8 @@
 #include "deviceplutosdrbox.h"
 
 DevicePlutoSDRBox::DevicePlutoSDRBox(const std::string& uri) :
+        m_lpfFIRRxGain(0),
+        m_lpfFIRTxGain(0),
         m_chnRx0(0),
         m_chnTx0(0),
         m_rxBuf(0),
@@ -470,7 +472,14 @@ void DevicePlutoSDRBox::setSampleRate(uint32_t sampleRate)
     m_devSampleRate = sampleRate;
 }
 
-void DevicePlutoSDRBox::setFIR(uint32_t sampleRate, uint32_t log2IntDec, uint32_t bw, int gain)
+/**
+ * @param sampleRate baseband sample rate (S/s)
+ * @param log2IntDec FIR interpolation or decimation factor
+ * @param use Rx or Tx. Applies to the rest of the parameters
+ * @param bw FIR filter bandwidth at approximately -6 dB cutoff (Hz)
+ * @param gain FIR filter gain (dB)
+ */
+void DevicePlutoSDRBox::setFIR(uint32_t sampleRate, uint32_t log2IntDec, DeviceUse use, uint32_t bw, int gain)
 {
     SampleRates sampleRates;
     std::ostringstream ostr;
@@ -479,11 +488,19 @@ void DevicePlutoSDRBox::setFIR(uint32_t sampleRate, uint32_t log2IntDec, uint32_
     double normalizedBW;
     uint32_t intdec = 1<<(log2IntDec > 2 ? 2 : log2IntDec);
 
+    // update gain parameter
+
+    if (use == USE_RX) {
+        m_lpfFIRRxGain = gain;
+    } else {
+        m_lpfFIRTxGain = gain;
+    }
+
     // set a dummy minimal filter first to get the sample rates right
 
     setFIREnable(false); // disable first
 
-    formatFIRHeader(ostr, intdec, gain);
+    formatFIRHeader(ostr, intdec);
     formatFIRCoefficients(ostr, 16, 0.5);
     setFilter(ostr.str());
     ostr.str(""); // reset string stream
@@ -515,13 +532,12 @@ void DevicePlutoSDRBox::setFIR(uint32_t sampleRate, uint32_t log2IntDec, uint32_
 
     // set the right filter
 
-    formatFIRHeader(ostr, intdec, gain);
+    formatFIRHeader(ostr, intdec);
     formatFIRCoefficients(ostr, nbTaps, normalizedBW);
     setFilter(ostr.str());
 
     m_lpfFIRlog2Decim = log2IntDec;
     m_lpfFIRBW = bw;
-    m_lpfFIRGain = gain;
 
     // enable and set sample rate will be done by the caller
 }
@@ -547,10 +563,10 @@ void DevicePlutoSDRBox::setLOPPMTenths(int ppmTenths)
     m_LOppmTenths = ppmTenths;
 }
 
-void DevicePlutoSDRBox::formatFIRHeader(std::ostringstream& ostr,uint32_t intdec, int32_t gain)
+void DevicePlutoSDRBox::formatFIRHeader(std::ostringstream& ostr,uint32_t intdec)
 {
-    ostr << "RX 3 GAIN " << gain << " DEC " << intdec << std::endl;
-    ostr << "TX 3 GAIN " << gain << " INT " << intdec << std::endl;
+    ostr << "RX 3 GAIN " << m_lpfFIRRxGain << " DEC " << intdec << std::endl;
+    ostr << "TX 3 GAIN " << m_lpfFIRTxGain << " INT " << intdec << std::endl;
 }
 
 void DevicePlutoSDRBox::formatFIRCoefficients(std::ostringstream& ostr, uint32_t nbTaps, double normalizedBW)

devices/plutosdr/deviceplutosdrbox.h

@@ -57,7 +57,8 @@ public:
     bool     m_lpfFIREnable;       //!< enable digital lowpass FIR filter
     float    m_lpfFIRBW;           //!< digital lowpass FIR filter bandwidth (Hz)
     uint32_t m_lpfFIRlog2Decim;    //!< digital lowpass FIR filter log2 of decimation factor (0..2)
-    int      m_lpfFIRGain;         //!< digital lowpass FIR filter gain (dB)
+    int      m_lpfFIRRxGain;       //!< digital lowpass FIR filter gain Rx side (dB)
+    int      m_lpfFIRTxGain;       //!< digital lowpass FIR filter gain Tx side (dB)
 
     DevicePlutoSDRBox(const std::string& uri);
     ~DevicePlutoSDRBox();
@@ -88,7 +89,7 @@ public:
     bool getRxSampleRates(SampleRates& sampleRates);
     bool getTxSampleRates(SampleRates& sampleRates);
     void setSampleRate(uint32_t sampleRate);
-    void setFIR(uint32_t sampleRate, uint32_t intdec, uint32_t bw, int gain);
+    void setFIR(uint32_t sampleRate, uint32_t intdec, DeviceUse use, uint32_t bw, int gain);
     void setFIREnable(bool enable);
     void setLOPPMTenths(int ppmTenths);
     bool getRSSI(std::string& rssiStr, unsigned int chan);
@@ -111,7 +112,7 @@ private:
 
     bool parseSampleRates(const std::string& rateStr, SampleRates& sampleRates);
     void setFilter(const std::string& filterConfigStr);
-    void formatFIRHeader(std::ostringstream& str, uint32_t intdec, int32_t gain);
+    void formatFIRHeader(std::ostringstream& str, uint32_t intdec);
     void formatFIRCoefficients(std::ostringstream& str, uint32_t nbTaps, double normalizedBW);
     void getXO();
     void setTracking();

plugins/samplesource/plutosdrinput/plutosdrinput.cpp

@@ -322,7 +322,7 @@ bool PlutoSDRInput::applySettings(const PlutoSDRInputSettings& settings, bool fo
         (settings.m_lpfFIRBW != m_settings.m_lpfFIRBW) ||
         (settings.m_lpfFIRGain != m_settings.m_lpfFIRGain) || force)
     {
-        plutoBox->setFIR(settings.m_devSampleRate, settings.m_lpfFIRlog2Decim, settings.m_lpfFIRBW, settings.m_lpfFIRGain); // don't bother with the FIR at this point
+        plutoBox->setFIR(settings.m_devSampleRate, settings.m_lpfFIRlog2Decim, DevicePlutoSDRBox::USE_RX, settings.m_lpfFIRBW, settings.m_lpfFIRGain);
         plutoBox->setFIREnable(settings.m_lpfFIREnable);   // eventually enable/disable FIR
         plutoBox->setSampleRate(settings.m_devSampleRate); // and set end point sample rate
 

plugins/samplesource/plutosdrinput/plutosdrinputgui.cpp

@@ -235,7 +235,7 @@ void PlutoSDRInputGui::on_lpFIRDecimation_currentIndexChanged(int index)
 
 void PlutoSDRInputGui::on_lpFIRGain_currentIndexChanged(int index)
 {
-    m_settings.m_lpfFIRGain = 6*(index > 1 ? 1 : index) - 6;
+    m_settings.m_lpfFIRGain = 6*(index > 3 ? 3 : index) - 12;
     sendSettings();
 }
 
@@ -276,7 +276,7 @@ void PlutoSDRInputGui::displaySettings()
     ui->lpFIREnable->setChecked(m_settings.m_lpfFIREnable);
     ui->lpFIR->setValue(m_settings.m_lpfFIRBW / 1000);
     ui->lpFIRDecimation->setCurrentIndex(m_settings.m_lpfFIRlog2Decim);
-    ui->lpFIRGain->setCurrentIndex((m_settings.m_lpfFIRGain + 6)/6);
+    ui->lpFIRGain->setCurrentIndex((m_settings.m_lpfFIRGain + 12)/6);
     ui->lpFIRDecimation->setEnabled(m_settings.m_lpfFIREnable);
     ui->lpFIRGain->setEnabled(m_settings.m_lpfFIREnable);
 

plugins/samplesource/plutosdrinput/plutosdrinputgui.ui

@@ -701,15 +701,14 @@
      </item>
      <item>
       <widget class="QComboBox" name="lpFIRGain">
-       <property name="maximumSize">
-        <size>
-         <width>50</width>
-         <height>16777215</height>
-        </size>
-       </property>
        <property name="toolTip">
         <string>FIR gain (dB)</string>
        </property>
+       <item>
+        <property name="text">
+         <string>-12</string>
+        </property>
+       </item>
        <item>
         <property name="text">
          <string>-6</string>
@@ -720,6 +719,11 @@
          <string>0</string>
         </property>
        </item>
+       <item>
+        <property name="text">
+         <string>+6</string>
+        </property>
+       </item>
       </widget>
      </item>
      <item>