Add master clock rate display to GUI.

Calculate full range of sample rates supported, by varying master clock.
Check if requested sample rate can be met.

devices/usrp/deviceusrp.cpp

@@ -52,7 +52,7 @@ void DeviceUSRP::enumOriginDevices(const QString& hardwareId, PluginInterface::O
             qDebug() << "DeviceUSRP::enumOriginDevices: found USRP device " << displayedName;
 
             DeviceUSRPParams usrpParams;
-            usrpParams.open(id.toStdString().c_str());
+            usrpParams.open(id.toStdString().c_str(), true);
             usrpParams.close();
 
             originDevices.append(PluginInterface::OriginDevice(

devices/usrp/deviceusrpparam.cpp

@@ -19,7 +19,7 @@
 #include <QDebug>
 #include "deviceusrpparam.h"
 
-bool DeviceUSRPParams::open(const char *deviceStr)
+bool DeviceUSRPParams::open(const char *deviceStr, bool channelNumOnly)
 {
     qDebug("DeviceUSRPParams::open: %s", (const char *) deviceStr);
 
@@ -32,37 +32,71 @@ bool DeviceUSRPParams::open(const char *deviceStr)
     m_nbRxChannels = m_dev->get_rx_num_channels();
     m_nbTxChannels = m_dev->get_tx_num_channels();
 
-    m_lpfRangeRx = m_dev->get_rx_bandwidth_range();
+    // Speed up program initialisation, by not getting all properties
-    m_lpfRangeTx = m_dev->get_tx_bandwidth_range();
+    // If we could find out number of channles without ::make ing the device
+    // that would be even better
+    if (!channelNumOnly)
+    {
+        m_lpfRangeRx = m_dev->get_rx_bandwidth_range();
+        m_lpfRangeTx = m_dev->get_tx_bandwidth_range();
 
-    m_loRangeRx = m_dev->get_fe_rx_freq_range();
+        m_loRangeRx = m_dev->get_fe_rx_freq_range();
-    m_loRangeTx = m_dev->get_fe_tx_freq_range();
+        m_loRangeTx = m_dev->get_fe_tx_freq_range();
 
-    m_srRangeRx = m_dev->get_rx_rates();
+        // For some devices (B210), rx/tx_rates vary with master_clock_rate
-    m_srRangeTx = m_dev->get_tx_rates();
+        // Note master_clock_rate is rate between FPGA and RFIC
+        // tx/rx_rate is rate between PC and FPGA
+        uhd::meta_range_t clockRange = m_dev->get_master_clock_rate_range();
+        if (clockRange.start() == clockRange.stop())
+        {
+            m_srRangeRx = m_dev->get_rx_rates();
+            m_srRangeTx = m_dev->get_tx_rates();
+        }
+        else
+        {
+            // Find max and min sample rate, for max and min master clock rates
+            m_dev->set_master_clock_rate(clockRange.start());
+            uhd::meta_range_t rxLow = m_dev->get_rx_rates();
+            uhd::meta_range_t txLow = m_dev->get_tx_rates();
 
-    m_gainRangeRx = m_dev->get_rx_gain_range();
+            m_dev->set_master_clock_rate(clockRange.stop());
-    m_gainRangeTx = m_dev->get_tx_gain_range();
+            uhd::meta_range_t rxHigh = m_dev->get_rx_rates();
+            uhd::meta_range_t txHigh = m_dev->get_tx_rates();
 
-    std::vector<std::string> txAntennas = m_dev->get_tx_antennas();
+            m_srRangeRx = uhd::meta_range_t(std::min(rxLow.start(), rxHigh.start()), std::max(rxLow.stop(), rxHigh.stop()));
-    m_txAntennas.reserve(txAntennas.size());
+            m_srRangeTx = uhd::meta_range_t(std::min(txLow.start(), txHigh.start()), std::max(txLow.stop(), txHigh.stop()));
-    for(size_t i = 0, l = txAntennas.size(); i < l; ++i)
-        m_txAntennas << QString::fromStdString(txAntennas[i]);
 
-    std::vector<std::string> rxAntennas = m_dev->get_rx_antennas();
+            // Need to restore automatic clock rate
-    m_rxAntennas.reserve(rxAntennas.size());
+            uhd::property_tree::sptr properties = m_dev->get_tree();
-    for(size_t i = 0, l = rxAntennas.size(); i < l; ++i)
+            if (properties->exists("/mboards/0/auto_tick_rate"))
-        m_rxAntennas << QString::fromStdString(rxAntennas[i]);
+            {
+                properties->access<bool>("/mboards/0/auto_tick_rate").set(true);
+            }
+        }
 
-    std::vector<std::string> rxGainNames = m_dev->get_rx_gain_names();
+        m_gainRangeRx = m_dev->get_rx_gain_range();
-    m_rxGainNames.reserve(rxGainNames.size());
+        m_gainRangeTx = m_dev->get_tx_gain_range();
-    for(size_t i = 0, l = rxGainNames.size(); i < l; ++i)
-        m_rxGainNames << QString::fromStdString(rxGainNames[i]);
 
-    std::vector<std::string> clockSources = m_dev->get_clock_sources(0);
+        std::vector<std::string> txAntennas = m_dev->get_tx_antennas();
-    m_clockSources.reserve(clockSources.size());
+        m_txAntennas.reserve(txAntennas.size());
-    for(size_t i = 0, l = clockSources.size(); i < l; ++i)
+        for(size_t i = 0, l = txAntennas.size(); i < l; ++i)
-        m_clockSources << QString::fromStdString(clockSources[i]);
+            m_txAntennas << QString::fromStdString(txAntennas[i]);
+
+        std::vector<std::string> rxAntennas = m_dev->get_rx_antennas();
+        m_rxAntennas.reserve(rxAntennas.size());
+        for(size_t i = 0, l = rxAntennas.size(); i < l; ++i)
+            m_rxAntennas << QString::fromStdString(rxAntennas[i]);
+
+        std::vector<std::string> rxGainNames = m_dev->get_rx_gain_names();
+        m_rxGainNames.reserve(rxGainNames.size());
+        for(size_t i = 0, l = rxGainNames.size(); i < l; ++i)
+            m_rxGainNames << QString::fromStdString(rxGainNames[i]);
+
+        std::vector<std::string> clockSources = m_dev->get_clock_sources(0);
+        m_clockSources.reserve(clockSources.size());
+        for(size_t i = 0, l = clockSources.size(); i < l; ++i)
+            m_clockSources << QString::fromStdString(clockSources[i]);
+    }
 
     return true;
 }

devices/usrp/deviceusrpparam.h

@@ -47,11 +47,6 @@ struct DEVICES_API DeviceUSRPParams
     uhd::meta_range_t m_srRangeTx;              //!< Sample rate range
     uhd::gain_range_t m_gainRangeRx;            //!< Gain range for Rx
     uhd::gain_range_t m_gainRangeTx;            //!< Gain range for Tx
-    float        m_sampleRate;                  //!< Sample rate between host and device
-    int          m_log2OvSRRx;                  //!< log2 of Rx oversampling (0..5)
-    int          m_log2OvSRTx;                  //!< log2 of Tx oversampling (0..5)
-    float        m_rxFrequency;                 //!< Rx frequency
-    float        m_txFrequency;                 //!< Tx frequency
     QStringList  m_txAntennas;                  //!< List of Tx antenna names
     QStringList  m_rxAntennas;                  //!< List of Rx antenna names
     QStringList  m_rxGainNames;                 //!< List of Rx gain stages - Currently this seems limited to "PGA"
@@ -61,11 +56,6 @@ struct DEVICES_API DeviceUSRPParams
         m_dev(),
         m_nbRxChannels(0),
         m_nbTxChannels(0),
-        m_sampleRate(1e6),
-        m_log2OvSRRx(0),
-        m_log2OvSRTx(0),
-        m_rxFrequency(1e6),
-        m_txFrequency(1e6),
         m_lpfRangeRx(),
         m_lpfRangeTx(),
         m_loRangeRx(),
@@ -84,7 +74,7 @@ struct DEVICES_API DeviceUSRPParams
     /**
      * Opens and initialize the device and obtain information (# channels, ranges, ...)
      */
-    bool open(const char *deviceStr);
+    bool open(const char *deviceStr, bool channelNumOnly);
     void close();
     uhd::usrp::multi_usrp::sptr getDevice() { return m_dev; }
 

devices/usrp/deviceusrpshared.h

@@ -37,18 +37,21 @@ public:
         int      getDevSampleRate() const { return m_devSampleRate; }
         uint64_t getCenterFrequency() const { return m_centerFrequency; }
         int      getLOOffset() const { return m_loOffset; }
+        int      getMasterClockRate() const { return m_masterClockRate; }
         bool getRxElseTx() const { return m_rxElseTx; }
 
         static MsgReportBuddyChange* create(
                 int devSampleRate,
                 uint64_t centerFrequency,
                 int loOffset,
+                int masterClockRate,
                 bool rxElseTx)
         {
             return new MsgReportBuddyChange(
                     devSampleRate,
                     centerFrequency,
                     loOffset,
+                    masterClockRate,
                     rxElseTx);
         }
 
@@ -56,17 +59,20 @@ public:
         int      m_devSampleRate;       //!< device/host sample rate
         uint64_t m_centerFrequency;     //!< Center frequency
         int      m_loOffset;            //!< LO offset
+        int      m_masterClockRate;     //!< FPGA/RFIC sample rate
         bool     m_rxElseTx;            //!< tells which side initiated the message
 
         MsgReportBuddyChange(
                 int devSampleRate,
                 uint64_t centerFrequency,
                 int loOffset,
+                int masterClockRate,
                 bool rxElseTx) :
             Message(),
             m_devSampleRate(devSampleRate),
             m_centerFrequency(centerFrequency),
             m_loOffset(loOffset),
+            m_masterClockRate(masterClockRate),
             m_rxElseTx(rxElseTx)
         { }
     };

plugins/samplesink/usrpoutput/usrpoutput.cpp

@@ -175,7 +175,7 @@ bool USRPOutput::openDevice()
         m_deviceShared.m_deviceParams = new DeviceUSRPParams();
         char serial[256];
         strcpy(serial, qPrintable(m_deviceAPI->getSamplingDeviceSerial()));
-        m_deviceShared.m_deviceParams->open(serial);
+        m_deviceShared.m_deviceParams->open(serial, false);
         m_deviceShared.m_channel = requestedChannel; // acknowledge the requested channel
     }
 
@@ -533,31 +533,31 @@ bool USRPOutput::handleMessage(const Message& message)
     {
         DeviceUSRPShared::MsgReportBuddyChange& report = (DeviceUSRPShared::MsgReportBuddyChange&) message;
 
-        if (report.getRxElseTx() && m_running)
+        if (!report.getRxElseTx())
-        {
-            double host_Hz;
-
-            host_Hz = m_deviceShared.m_deviceParams->getDevice()->get_tx_rate(m_deviceShared.m_channel);
-            m_settings.m_devSampleRate = roundf(host_Hz);
-
-            qDebug() << "USRPOutput::handleMessage: MsgReportBuddyChange:"
-                     << " m_devSampleRate: " << m_settings.m_devSampleRate;
-        }
-        else
         {
+            // Tx buddy changed settings, we need to copy
             m_settings.m_devSampleRate   = report.getDevSampleRate();
             m_settings.m_centerFrequency = report.getCenterFrequency();
             m_settings.m_loOffset        = report.getLOOffset();
         }
+        // Master clock rate is common between all buddies
+        int masterClockRate = report.getMasterClockRate();
+        if (masterClockRate > 0)
+            m_settings.m_masterClockRate = masterClockRate;
+        qDebug() << "USRPOutput::handleMessage MsgReportBuddyChange";
+        qDebug() << "m_masterClockRate " << m_settings.m_masterClockRate;
 
         DSPSignalNotification *notif = new DSPSignalNotification(
                 m_settings.m_devSampleRate/(1<<m_settings.m_log2SoftInterp),
                 m_settings.m_centerFrequency);
         m_deviceAPI->getDeviceEngineInputMessageQueue()->push(notif);
 
-        DeviceUSRPShared::MsgReportBuddyChange *reportToGUI = DeviceUSRPShared::MsgReportBuddyChange::create(
+        if (getMessageQueueToGUI())
-                m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, false);
+        {
-        getMessageQueueToGUI()->push(reportToGUI);
+            DeviceUSRPShared::MsgReportBuddyChange *reportToGUI = DeviceUSRPShared::MsgReportBuddyChange::create(
+                    m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset,  m_settings.m_masterClockRate, false);
+            getMessageQueueToGUI()->push(reportToGUI);
+        }
 
         return true;
     }
@@ -617,6 +617,7 @@ bool USRPOutput::applySettings(const USRPOutputSettings& settings, bool preGetSt
     bool forwardChangeAllDSP = false;
     bool forwardClockSource  = false;
     bool ownThreadWasRunning = false;
+    bool checkRates          = false;
     QList<QString> reverseAPIKeys;
 
     try
@@ -665,10 +666,8 @@ bool USRPOutput::applySettings(const USRPOutputSettings& settings, bool preGetSt
             if (m_deviceShared.m_deviceParams->getDevice() && (m_channelAcquired || preGetStream))
             {
                 m_deviceShared.m_deviceParams->getDevice()->set_tx_rate(settings.m_devSampleRate, m_deviceShared.m_channel);
-                double actualSampleRate = m_deviceShared.m_deviceParams->getDevice()->get_tx_rate(m_deviceShared.m_channel);
+                qDebug("USRPOutput::applySettings: set sample rate set to %d", settings.m_devSampleRate);
-                qDebug("USRPOutput::applySettings: set sample rate set to %d - actual rate %f", settings.m_devSampleRate,
+                checkRates = true;
-                        actualSampleRate);
-                m_deviceShared.m_deviceParams->m_sampleRate = m_settings.m_devSampleRate;
             }
         }
 
@@ -776,6 +775,17 @@ bool USRPOutput::applySettings(const USRPOutputSettings& settings, bool preGetSt
 
         m_settings = settings;
 
+        if (checkRates)
+        {
+            // Check if requested rate could actually be met and what master clock rate we ended up with
+            double actualSampleRate = m_deviceShared.m_deviceParams->getDevice()->get_tx_rate(m_deviceShared.m_channel);
+            qDebug("USRPOutput::applySettings: actual sample rate %f", actualSampleRate);
+            double masterClockRate = m_deviceShared.m_deviceParams->getDevice()->get_master_clock_rate();
+            qDebug("USRPOutput::applySettings: master_clock_rate %f", masterClockRate);
+            m_settings.m_devSampleRate = actualSampleRate;
+            m_settings.m_masterClockRate = masterClockRate;
+        }
+
         // forward changes to buddies or oneself
 
         if (forwardChangeAllDSP)
@@ -795,7 +805,7 @@ bool USRPOutput::applySettings(const USRPOutputSettings& settings, bool preGetSt
             for (; itSink != sinkBuddies.end(); ++itSink)
             {
                 DeviceUSRPShared::MsgReportBuddyChange *report = DeviceUSRPShared::MsgReportBuddyChange::create(
-                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, false);
+                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, m_settings.m_masterClockRate, false);
                 (*itSink)->getSamplingDeviceInputMessageQueue()->push(report);
             }
 
@@ -806,9 +816,17 @@ bool USRPOutput::applySettings(const USRPOutputSettings& settings, bool preGetSt
             for (; itSource != sourceBuddies.end(); ++itSource)
             {
                 DeviceUSRPShared::MsgReportBuddyChange *report = DeviceUSRPShared::MsgReportBuddyChange::create(
-                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, false);
+                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, m_settings.m_masterClockRate, false);
                 (*itSource)->getSamplingDeviceInputMessageQueue()->push(report);
             }
+
+            // send to GUI so it can see master clock rate and if actual rate differs
+            if (m_deviceAPI->getSamplingDeviceGUIMessageQueue())
+            {
+                DeviceUSRPShared::MsgReportBuddyChange *report = DeviceUSRPShared::MsgReportBuddyChange::create(
+                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, m_settings.m_masterClockRate, false);
+                m_deviceAPI->getSamplingDeviceGUIMessageQueue()->push(report);
+            }
         }
         else if (forwardChangeTxDSP)
         {
@@ -827,7 +845,7 @@ bool USRPOutput::applySettings(const USRPOutputSettings& settings, bool preGetSt
             for (; itSink != sinkBuddies.end(); ++itSink)
             {
                 DeviceUSRPShared::MsgReportBuddyChange *report = DeviceUSRPShared::MsgReportBuddyChange::create(
-                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, false);
+                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, m_settings.m_masterClockRate, false);
                 (*itSink)->getSamplingDeviceInputMessageQueue()->push(report);
             }
         }
@@ -856,6 +874,14 @@ bool USRPOutput::applySettings(const USRPOutputSettings& settings, bool preGetSt
                 }
             }
 
+            // send to GUI in case requested clock isn't detected
+            if (m_deviceAPI->getSamplingDeviceGUIMessageQueue())
+            {
+                DeviceUSRPShared::MsgReportClockSourceChange *report = DeviceUSRPShared::MsgReportClockSourceChange::create(
+                        m_settings.m_clockSource);
+                m_deviceAPI->getSamplingDeviceGUIMessageQueue()->push(report);
+            }
+
             // send to source buddies
             const std::vector<DeviceAPI*>& sourceBuddies = m_deviceAPI->getSourceBuddies();
             std::vector<DeviceAPI*>::const_iterator itSource = sourceBuddies.begin();

plugins/samplesink/usrpoutput/usrpoutputgui.cpp

@@ -180,9 +180,10 @@ bool USRPOutputGUI::handleMessage(const Message& message)
     else if (DeviceUSRPShared::MsgReportBuddyChange::match(message))
     {
         DeviceUSRPShared::MsgReportBuddyChange& report = (DeviceUSRPShared::MsgReportBuddyChange&) message;
-        m_settings.m_devSampleRate = report.getDevSampleRate();
+        m_settings.m_masterClockRate = report.getMasterClockRate();
 
         if (!report.getRxElseTx()) {
+            m_settings.m_devSampleRate   = report.getDevSampleRate();
             m_settings.m_centerFrequency = report.getCenterFrequency();
             m_settings.m_loOffset        = report.getLOOffset();
         }
@@ -291,12 +292,20 @@ void USRPOutputGUI::updateSampleRateAndFrequency()
 void USRPOutputGUI::updateSampleRate()
 {
     uint32_t sr = m_settings.m_devSampleRate;
+    int cr = m_settings.m_masterClockRate;
 
     if (sr < 100000000) {
         ui->sampleRateLabel->setText(tr("%1k").arg(QString::number(sr / 1000.0f, 'g', 5)));
     } else {
         ui->sampleRateLabel->setText(tr("%1M").arg(QString::number(sr / 1000000.0f, 'g', 5)));
     }
+    if (cr < 0) {
+       ui->masterClockRateLabel->setText("-");
+    } else if (cr < 100000000) {
+        ui->masterClockRateLabel->setText(tr("%1k").arg(QString::number(cr / 1000.0f, 'g', 5)));
+    } else {
+        ui->masterClockRateLabel->setText(tr("%1M").arg(QString::number(cr / 1000000.0f, 'g', 5)));
+    }
     // LO offset shouldn't be greater than half the sample rate
     ui->loOffset->setValueRange(false, 5, -(int32_t)sr/2/1000, (int32_t)sr/2/1000);
 }

plugins/samplesink/usrpoutput/usrpoutputgui.ui

@@ -75,6 +75,16 @@
        </item>
        <item>
         <layout class="QHBoxLayout" name="freqLeftBotLayout">
+         <item>
+          <widget class="QLabel" name="masterClockRateLabel">
+           <property name="toolTip">
+            <string>Master clock rate (sample rate between FPGA and RFIC) (k or MS/s)</string>
+           </property>
+           <property name="text">
+            <string>00000k</string>
+           </property>
+          </widget>
+         </item>
          <item>
           <widget class="QLabel" name="sampleRateLabel">
            <property name="minimumSize">

plugins/samplesink/usrpoutput/usrpoutputsettings.cpp

@@ -27,6 +27,7 @@ USRPOutputSettings::USRPOutputSettings()
 
 void USRPOutputSettings::resetToDefaults()
 {
+    m_masterClockRate = -1; // Calculated by UHD
     m_centerFrequency = 435000*1000;
     m_devSampleRate = 3000000;
     m_loOffset = 0;

plugins/samplesink/usrpoutput/usrpoutputsettings.h

@@ -30,6 +30,7 @@
  */
 struct USRPOutputSettings
 {
+    int      m_masterClockRate;
     // global settings to be saved
     uint64_t m_centerFrequency;
     int      m_devSampleRate;

plugins/samplesource/usrpinput/usrpinput.cpp

@@ -202,7 +202,7 @@ bool USRPInput::openDevice()
         m_deviceShared.m_deviceParams = new DeviceUSRPParams();
         char serial[256];
         strcpy(serial, qPrintable(m_deviceAPI->getSamplingDeviceSerial()));
-        m_deviceShared.m_deviceParams->open(serial);
+        m_deviceShared.m_deviceParams->open(serial, false);
         m_deviceShared.m_channel = requestedChannel; // acknowledge the requested channel
     }
 
@@ -548,20 +548,17 @@ bool USRPInput::handleMessage(const Message& message)
 
         if (report.getRxElseTx())
         {
+            // Rx buddy changed settings, we need to copy
             m_settings.m_devSampleRate   = report.getDevSampleRate();
             m_settings.m_centerFrequency = report.getCenterFrequency();
             m_settings.m_loOffset        = report.getLOOffset();
         }
-        else if (m_running)
+        // Master clock rate is common between all buddies
-        {
+        int masterClockRate = report.getMasterClockRate();
-            double host_Hz;
+        if (masterClockRate > 0)
-
+            m_settings.m_masterClockRate = masterClockRate;
-            host_Hz = m_deviceShared.m_deviceParams->getDevice()->get_rx_rate(m_deviceShared.m_channel);
+        qDebug() << "USRPInput::handleMessage MsgReportBuddyChange";
-            m_settings.m_devSampleRate = roundf(host_Hz);
+        qDebug() << "m_masterClockRate " << m_settings.m_masterClockRate;
-
-            qDebug() << "USRPInput::handleMessage: MsgReportBuddyChange:"
-                     << " m_devSampleRate: " << m_settings.m_devSampleRate;
-        }
 
         DSPSignalNotification *notif = new DSPSignalNotification(
                 m_settings.m_devSampleRate/(1<<m_settings.m_log2SoftDecim),
@@ -571,7 +568,7 @@ bool USRPInput::handleMessage(const Message& message)
         if (getMessageQueueToGUI())
         {
             DeviceUSRPShared::MsgReportBuddyChange *reportToGUI = DeviceUSRPShared::MsgReportBuddyChange::create(
-                    m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, true);
+                    m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, m_settings.m_masterClockRate, true);
             getMessageQueueToGUI()->push(reportToGUI);
         }
 
@@ -656,6 +653,7 @@ bool USRPInput::applySettings(const USRPInputSettings& settings, bool preGetStre
     bool forwardClockSource  = false;
     bool ownThreadWasRunning = false;
     bool reapplySomeSettings = false;
+    bool checkRates          = false;
     QList<QString> reverseAPIKeys;
 
     try
@@ -704,10 +702,8 @@ bool USRPInput::applySettings(const USRPInputSettings& settings, bool preGetStre
             if (m_deviceShared.m_deviceParams->getDevice() && (m_channelAcquired || preGetStream))
             {
                 m_deviceShared.m_deviceParams->getDevice()->set_rx_rate(settings.m_devSampleRate, m_deviceShared.m_channel);
-                double actualSampleRate = m_deviceShared.m_deviceParams->getDevice()->get_rx_rate(m_deviceShared.m_channel);
+                qDebug("USRPInput::applySettings: set sample rate set to %d", settings.m_devSampleRate);
-                qDebug("USRPInput::applySettings: set sample rate set to %d - actual rate %f", settings.m_devSampleRate,
+                checkRates = true;
-                        actualSampleRate);
-                m_deviceShared.m_deviceParams->m_sampleRate = m_settings.m_devSampleRate;
                 reapplySomeSettings = true;
             }
         }
@@ -845,6 +841,17 @@ bool USRPInput::applySettings(const USRPInputSettings& settings, bool preGetStre
 
         m_settings = settings;
 
+        if (checkRates)
+        {
+            // Check if requested rate could actually be met and what master clock rate we ended up with
+            double actualSampleRate = m_deviceShared.m_deviceParams->getDevice()->get_rx_rate(m_deviceShared.m_channel);
+            qDebug("USRPInput::applySettings: actual sample rate %f", actualSampleRate);
+            double masterClockRate = m_deviceShared.m_deviceParams->getDevice()->get_master_clock_rate();
+            qDebug("USRPInput::applySettings: master_clock_rate %f", masterClockRate);
+            m_settings.m_devSampleRate = actualSampleRate;
+            m_settings.m_masterClockRate = masterClockRate;
+        }
+
         // forward changes to buddies or oneself
 
         if (forwardChangeAllDSP)
@@ -864,7 +871,7 @@ bool USRPInput::applySettings(const USRPInputSettings& settings, bool preGetStre
             for (; itSource != sourceBuddies.end(); ++itSource)
             {
                 DeviceUSRPShared::MsgReportBuddyChange *report = DeviceUSRPShared::MsgReportBuddyChange::create(
-                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, true);
+                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, m_settings.m_masterClockRate, true);
                 (*itSource)->getSamplingDeviceInputMessageQueue()->push(report);
             }
 
@@ -875,9 +882,17 @@ bool USRPInput::applySettings(const USRPInputSettings& settings, bool preGetStre
             for (; itSink != sinkBuddies.end(); ++itSink)
             {
                 DeviceUSRPShared::MsgReportBuddyChange *report = DeviceUSRPShared::MsgReportBuddyChange::create(
-                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, true);
+                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, m_settings.m_masterClockRate, true);
                 (*itSink)->getSamplingDeviceInputMessageQueue()->push(report);
             }
+
+            // send to GUI so it can see master clock rate and if actual rate differs
+            if (m_deviceAPI->getSamplingDeviceGUIMessageQueue())
+            {
+                DeviceUSRPShared::MsgReportBuddyChange *report = DeviceUSRPShared::MsgReportBuddyChange::create(
+                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, m_settings.m_masterClockRate, true);
+                m_deviceAPI->getSamplingDeviceGUIMessageQueue()->push(report);
+            }
         }
         else if (forwardChangeRxDSP)
         {
@@ -896,7 +911,7 @@ bool USRPInput::applySettings(const USRPInputSettings& settings, bool preGetStre
             for (; itSource != sourceBuddies.end(); ++itSource)
             {
                 DeviceUSRPShared::MsgReportBuddyChange *report = DeviceUSRPShared::MsgReportBuddyChange::create(
-                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, true);
+                        m_settings.m_devSampleRate, m_settings.m_centerFrequency, m_settings.m_loOffset, m_settings.m_masterClockRate, true);
                 (*itSource)->getSamplingDeviceInputMessageQueue()->push(report);
             }
         }

plugins/samplesource/usrpinput/usrpinputgui.cpp

@@ -163,9 +163,10 @@ bool USRPInputGUI::handleMessage(const Message& message)
     else if (DeviceUSRPShared::MsgReportBuddyChange::match(message))
     {
         DeviceUSRPShared::MsgReportBuddyChange& report = (DeviceUSRPShared::MsgReportBuddyChange&) message;
-        m_settings.m_devSampleRate = report.getDevSampleRate();
+        m_settings.m_masterClockRate = report.getMasterClockRate();
 
         if (report.getRxElseTx()) {
+            m_settings.m_devSampleRate   = report.getDevSampleRate();
             m_settings.m_centerFrequency = report.getCenterFrequency();
             m_settings.m_loOffset        = report.getLOOffset();
         }
@@ -287,12 +288,20 @@ void USRPInputGUI::handleInputMessages()
 void USRPInputGUI::updateSampleRate()
 {
     uint32_t sr = m_settings.m_devSampleRate;
+    int cr = m_settings.m_masterClockRate;
 
     if (sr < 100000000) {
         ui->sampleRateLabel->setText(tr("%1k").arg(QString::number(sr / 1000.0f, 'g', 5)));
     } else {
         ui->sampleRateLabel->setText(tr("%1M").arg(QString::number(sr / 1000000.0f, 'g', 5)));
     }
+    if (cr < 0) {
+       ui->masterClockRateLabel->setText("-");
+    } else if (cr < 100000000) {
+        ui->masterClockRateLabel->setText(tr("%1k").arg(QString::number(cr / 1000.0f, 'g', 5)));
+    } else {
+        ui->masterClockRateLabel->setText(tr("%1M").arg(QString::number(cr / 1000000.0f, 'g', 5)));
+    }
     // LO offset shouldn't be greater than half the sample rate
     ui->loOffset->setValueRange(false, 5, -(int32_t)sr/2/1000, (int32_t)sr/2/1000);
 }

plugins/samplesource/usrpinput/usrpinputgui.ui

@@ -75,6 +75,16 @@
        </item>
        <item>
         <layout class="QHBoxLayout" name="freqLeftBotLayout">
+         <item>
+          <widget class="QLabel" name="masterClockRateLabel">
+           <property name="toolTip">
+            <string>Master clock rate (sample rate between FPGA and RFIC) (k or MS/s)</string>
+           </property>
+           <property name="text">
+            <string>00000k</string>
+           </property>
+          </widget>
+         </item>
          <item>
           <widget class="QLabel" name="sampleRateLabel">
            <property name="minimumSize">
@@ -799,17 +809,17 @@
    <header>gui/valuedial.h</header>
    <container>1</container>
   </customwidget>
-  <customwidget>
-   <class>TransverterButton</class>
-   <extends>QPushButton</extends>
-   <header>gui/transverterbutton.h</header>
-  </customwidget>
   <customwidget>
    <class>ValueDialZ</class>
    <extends>QWidget</extends>
    <header>gui/valuedialz.h</header>
    <container>1</container>
   </customwidget>
+  <customwidget>
+   <class>TransverterButton</class>
+   <extends>QPushButton</extends>
+   <header>gui/transverterbutton.h</header>
+  </customwidget>
  </customwidgets>
  <resources>
   <include location="../../../sdrgui/resources/res.qrc"/>

plugins/samplesource/usrpinput/usrpinputsettings.cpp

@@ -26,6 +26,7 @@ USRPInputSettings::USRPInputSettings()
 
 void USRPInputSettings::resetToDefaults()
 {
+    m_masterClockRate = -1; // Calculated by UHD
     m_centerFrequency = 435000*1000;
     m_devSampleRate = 3000000;
     m_loOffset = 0;

plugins/samplesource/usrpinput/usrpinputsettings.h

@@ -34,6 +34,7 @@ struct USRPInputSettings
         GAIN_MANUAL
     } GainMode;
 
+    int      m_masterClockRate;
     // global settings to be saved
     uint64_t m_centerFrequency;
     int      m_devSampleRate;