Using the LimeSDR-USB in both sink and source blocks with the TX output connected externally by cable to the RX input exhibits unexpected (for me) behavior. Similar behavior is also seen with the LimeSDR-USB in sink and LimeSDR XTRX in source but additional features in the XTRX source output complicate observation. LimesuiteNG (d337d750) was built and installed after gnuradio 3.10.12.0. The left graph in the displays below is the Re and Im test signal applied to the sink block and the right is of the source block output.
Input with zero phase
Input with phase between zero and 90 degrees (phase quadrature)
Input with phase between 90 and 180 degrees
Input with phase 180 degrees
Input phase 90 degrees
Can anyone comment on whether this operation is indeed unexpected? The flow graph that is responsible for these runs is simpleSDRtest.grc and is available at GitHub - rsmegal/gr-limesuiteng-validation: Testing and validation of GRC LimeSDR block..