Among other things, the GMSK Mod block expects packed bytes. Remove the Map block and add an Unpacked to Packed block in its place. The filter parameters on the receiver are also incorrect and will filter out most of your signal.
In general, every time you make a change you must view the baseband spectrum and time domain signal (at least) to confirm that the change you expect is the change you see. Nick On Wed, Feb 3, 2021 at 7:26 AM kaihua cheng <kaihua...@gmail.com> wrote: > Hello, I want to build a transceiver by using CCSDS and GMSK. I have no > problem with running CCSDS alone. But once I add GMSK, the decoding is > completely off. can someone help me with it? below is the attachment! > thank you >