Please see here for further/background information.

Sample file is here . Sample rate is 19,200; symbol rate is 4,800; (sps = 4)

First image in each pair is constellation output from the differential decoder (rx_diffdec.dat); second is same except rendered as float with amplitude components discarded.

First two images are results of our (op25) custom Gardner timing recovery/Costas loop block

Next two images are for the new dqpsk2 blocks

Next two images are for the old dqpsk blocks