[LimeSDR-Mini] RF Loopback with single LO

#1

Howdy,

I’m interested in using a LimeSDR-mini for some phase-coherent radar.
For this I’d like to transmit and receive simultaneously using a single LO for both TX and RX.

It seems that using a single LO is possible according to this discussion regarding TDD mode: https://discourse.myriadrf.org/t/limesdr-usb-synchronization-and-toggle-tdd-fdd-mode/1791/5

However, my understanding of TDD mode is that TX and RX operations would happen right after each other, so it’s not clear to me whether this allows simultaneous operation.

Is it possible to transmit and receive using the same LO on the LimeSDR-Mini and receive meaningful data? If so, is the linked explanation the best way to go about it?

Is this possibly dangerous to my device?

Thanks!

#2

Hi,
There is no automatic Tx/Rx switching in LimeSDR. The TDD mode mentioned in the linked post only switches to using Tx PLL for both Tx and Rx . So both Tx and Rx work at the same time, just from a single PLL.
Also, when using SoapySDR or LMS API, usage of single PLL should be enabled when Tx and Rx frequencies are set to the same value, without a need to edit any additional setting.