GPSDO synchronization with LimeSDR-USB

Given a 2.5 volt p-p GPSDO 10 MHz signal to the Osc. In port, what Python command can be used to ‘lock in’ that signal to the internal VCXO of Lime? Also, once that command is given what command can be used to confirm that it has occurred?

No idea with Python and I suspect it will depend on what library you are using. But to give you an example, you can find the native LMS API driver for the LibreCellular srsRAN fork here (device “lime”):

With this we can just specify refclk=10e6 as a driver argument to set an external reference. See:

If successful and the SDR locks, you will see an LED illuminate.

Before switching to the lime API version of srsRAN I was using LimeUtil to switch to the refclk input, which has an option for it:

LimeUtil --refclk --fref 10000000

After which SoapySDR seemed to just carry on as normal.

Not sure if that same command confirms the lock status though I’m afraid.

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