FAQs from Rohde & Schwarz

CMWrun Settings for external Interfer usage in Bluetooth LE Test Plans

Question

Is it possible to set up LE Interferer tests in CMWrun using the CMW GPRF capabilities?

Answer

Some Bluetooth LE CMWrun tests require multiple interference signal sources which can come from standalone signal generators. Alternatively, one can also use the CMW270/290/500 GPRF Generator capabilities for this purpose. Below one example of such test highlighted in the CMWrun Help.

If not properly set, this may drive into a HW conflict in the CMW since the architecture does not allow multiple applications to handle simultaneously the same RFTX Converter. Here a short example on how this may appear in the GUI if such conflict shows up while trying to set an interfer from the GPRF Generator while also having opened the BT Signaling Application.

The recommendation is then to work with Virtual Connectors in CMWrun, this is available under Resources -> CMW Instrument.

Later one can configure this accordingly in the different properties inside the test plan, see below example.

Bluetooth Connection Setup for LE
Advanced configuration

The above field “Ext. Attenuation Out(db)” is of particular interest and will be used together with the values available for Attenuation versus frequency inside the TC Config for the total Attenuation applied to RF_OUT_B.

CMWrun uses this compound value accordingly to adjust the power level inside GPRF or in the external generator in accordance with the LE Specification.

References

  • CMW270/290/500 User Manuals available in Gloris MRT website
  • CMWrun GUI Embedded Help
  • Bluetooth LE Specification