Time Synchronized Multi LimeSDR

I have the following requirement:

  1. I want to capture two chunks of spectrum, from two widely separated GSM bands GSM900 and DCS1800

e.g. I want to capture at center frequency 930Mhz with 5 MHz sample rate and center frequency 1812MHz with 5 Mhz sample rate

  1. I need the captures to be synchronized. Now I understand to achieve this we can use a single clock source to drive two LimeSDRs.

  2. I also need the captures to be time synchronized, how can time synchronization be achieved ?
    i) One solution I have seen that people use with RTL SDR is that, they first tune both Rx receivers to a single frequency like some beacon signal. Cross correlate the received signals and find out the time difference, thus synchronizing both captures, and then changing Rx frequencies to desired frequencies on the fly.
    ii) Is there any better way to achieve time synchronization using LimeSDR ?

I have read multiple relevant posts in this forum but could not find a clear answer

Check Synchronize two LimeSDR, especially

where a timestamp reset is done through GPIO. This does require a modification in the gateware but it’s quite limited. cmichal even posted the binary gateware here:


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