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Problem when loading simulations on FlexDCA

Question asked by abdallahLB on Oct 3, 2019



I discovered today when I try to load some simulations for 53G PAM4 signals that I have saved before that when reloading them again to FlexDCA there is  two big issues. one I success to find a solution for it but the second is not.


1- when loading a simulation, FlexDCA doesn't take into consideration the intrinsic noise value of the channel although it is saved in the simulation, so when measuring TDECQ, the algorithm assume intrinsic noise to be null so the results is wrong. I bypass that problem by calculating TDECQ manually using the TDECQ formula as defined in IEEE, so I am using outer OMA, and the minimum between added left and right sigmas, and the intrinsic noise of the used channel so I obtain what TDECQ should be.



2- The second and the biggest problem when loading a simulation although it may been saved in the DCA itself, the signal looks low noisy and the factor of noise reduction is exactly equal 1/sqrt(2) or 0.707. After analyzing a lot of captures I discovered that there is a kind of averaging is applied on simulations when loading them the filter is applied internally, exactly it is low pass filter of 2 taps (0.5, 0.5) or as it is known moving average filter of window size equal two. I don't really understand why that type of filter is forced to be applied on each simulation so data are changing always.


I hope really you clarify why that happened and how to disable these features.