Fix b200mini external clock

lib/src/phy/rf/rf_uhd_generic.h

@@ -48,7 +48,6 @@ private:
 
   uhd_error test_ad936x_device(uint32_t nof_channels)
   {
-
     uhd_error err = set_rx_rate(1.92e6);
     if (err != UHD_ERROR_NONE) {
       return err;
@@ -209,7 +208,6 @@ public:
       Info("The device is based on AD9361, get RX stream for checking LIBUSB_TRANSFER_ERROR");
       uint32_t ntrials = 10;
       do {
-
         // If no error getting RX stream, return
         err = test_ad936x_device(nof_channels);
         if (err == UHD_ERROR_NONE) {
@@ -268,13 +266,13 @@ public:
   {
     UHD_SAFE_C_SAVE_ERROR(this, timespec = usrp->get_time_now();)
   }
-  uhd_error set_sync_source(const std::string& source) override
+  uhd_error set_sync_source(const std::string& sync_source, const std::string& clock_source) override
   {
-    Debug("Setting PPS source to '" << source << "'");
+    Debug("Setting PPS source to '" << sync_source << "' and clock source to '" << clock_source << "'");
 #if UHD_VERSION < 3140099
-        UHD_SAFE_C_SAVE_ERROR(this, usrp->set_clock_source(source); usrp->set_time_source(source);)
+    UHD_SAFE_C_SAVE_ERROR(this, usrp->set_clock_source(clock_source); usrp->set_time_source(sync_source);)
 #else
-        UHD_SAFE_C_SAVE_ERROR(this, usrp->set_sync_source(source, source);)
+    UHD_SAFE_C_SAVE_ERROR(this, usrp->set_sync_source(clock_source, sync_source);)
 #endif
   }
   uhd_error get_gain_range(uhd::gain_range_t& tx_gain_range, uhd::gain_range_t& rx_gain_range) override

lib/src/phy/rf/rf_uhd_imp.cc

@@ -603,6 +603,12 @@ static int uhd_init(rf_uhd_handler_t* handler, char* args, uint32_t nof_channels
     clock_src = device_addr.pop("clock");
   }
 
+  // Select same synchronization source only if more than one channel is opened
+  std::string sync_src = "internal";
+  if (nof_channels > 1) {
+    sync_src = clock_src;
+  }
+
   // Logging level
 #ifdef UHD_LOG_INFO
   uhd::log::severity_level severity_level = uhd::log::severity_level::info;
@@ -779,7 +785,7 @@ static int uhd_init(rf_uhd_handler_t* handler, char* args, uint32_t nof_channels
   std::string sensor_name;
 
   // Set sync source
-  if (handler->uhd->set_sync_source(clock_src) != UHD_ERROR_NONE) {
+  if (handler->uhd->set_sync_source(sync_src, clock_src) != UHD_ERROR_NONE) {
     print_usrp_error(handler);
     return SRSRAN_ERROR;
   }

lib/src/phy/rf/rf_uhd_safe.h

@@ -143,7 +143,7 @@ public:
                           stream_cmd.stream_now = true;
                           rx_stream->issue_stream_cmd(stream_cmd);)
   }
-  virtual uhd_error set_sync_source(const std::string& source)                                         = 0;
+  virtual uhd_error set_sync_source(const std::string& sync_source, const std::string& clock_source)   = 0;
   virtual uhd_error get_gain_range(uhd::gain_range_t& tx_gain_range, uhd::gain_range_t& rx_gain_range) = 0;
   virtual uhd_error set_master_clock_rate(double rate)                                                 = 0;
   virtual uhd_error set_rx_rate(double rate)                                                           = 0;