Re: Only one point in a S-Band BPSK constellation

[Jeff Long]

Check the cutoff frequency and transition frequency on the rx filter. That's not what you want, and it's unlikely your computer can run a filter that tight at 8MS/s in real time.

On Wed, Apr 19, 2023, 12:03 יותם זיס <yotam.zyss@gmail.com> wrote:

Hello, we're students trying to build an S-Band BPSK modem.

Transmitting using UHD-USRP b200 and receiving with Lime-SDR Mini.

We have a problem when working with a high bitrate, 1Mbps with 8 sps:

Only one point is showing up in the constellation. When we worked in 9600bps it worked just fine.

In addition we're also using gr-lfast blocks to make it possible to run our program without maxing out the CPU.

Attached screenshots of our uplink and downlink flowgraphs and the GUI.

Thanks and 73