Hi Boldoo, the main functions of DSP are forward error correction (FEC) encoding, constellation mapping (MAP), fiber nonlinearity compensation (NLC), up-sampling (UpS), electronic dispersion precompensation (EDC), Nyquist prefiltering. As far as I know there is no DSP in OptiSustem. This component (written in Matlab) can be found in ‘100 Gbps DP-QPSK System with DSP’ example.