LimeSDR heavily distorts signals on TX. For example, I created this graph, which outputs single-side BPSK random signal:
Output of FFT plot is:
But real spectrum is heavily distorted on left side:
For more confusion, running TxTSP BIST (Build-in self-test) (“Start BIST” on “TxTSP” tab in LimeSuite) helps a little bit:
For reference, this is output of HackRF One (Blue) with the same graph:
Much cleaner and better signal.
Can someone give a hint why LimeSDR distorts signal so much? And how starting BIST changes something?
(LimeSDR-USB FW:3 HW:4 Protocol:1 GW:2 GW_rev:10 Ref Clk: 30.72 MHz)