Hello,
Thanks for reaching out to us.
In order to connect your matlab component to PRBS, you need to define the input signals correctly inside the code. For better understanding on how to use the matlab component, I advise you to refer our matlab examples, found in the directory: C:\Users\USERNAME\Documents\OptiSystem 22.0 Samples\Software interworking\MATLAB co-simulation
You can also have a look at the following document to understand how to define the input ports and output ports for the signals (optical, electrical, bianry): C:\Users\USERNAME\Documents\OptiSystem 22.0 Samples\Software interworking\MATLAB co-simulation\OptiSystem MATLAB data model\OptiSystem-MATLAB Data Model 7 July 2017.pdf
I hope this helps?
Warm Regards,
Saurabh Bedi.