HDL optimized QPSK TX and RX combined

Hi,

I am trying to simulate example HDL optimized qpsk Tx and HDL QPSK optimized RX by interconnecting them as written in Rx webpage.

The problem I am facing is that I am not getting a nice time recovery contellation plot. I read a post online (https://itectec.com/matlab/matlab-correct-samples-for-hdl-optimized-qpsk-receiver-with-captured-data/) about it which suggested to add a delay element inbetween but for me it didnot worked.

I have attached my block diagram and screen shot for the said diagram.

matfile is attached incase if you need.

[Muhammad Rizwan]

I also observed low BER rates too though they are simply interconnected.

Answer 1

[Kranti Balaga]

Hi,

There are some limitations in the model due to receiver architecture. Here, Timing recovery would be self synchronizing and perform before the carrier synchronization that would have been improved the frequency offset estimation and link performance. We enhance this example in R21a and performance got improved and as expected. The following is the example link, you can take a look at

https://www.mathworks.com/help/comm/ug/hdlqpsktransmitterreceiver.html