hi raja
i have a question , you said " In your plot ripple is around 1ps". but,according to the plot, the ripple is about 1ns. why you said the ripple is 1ps. why have 10e-3 difference. i have saw some paper, all have 10e-3 difference. i can't understand , or can you offer me some document which i can get the answer from . thank you
raja.cedt wrote on Dec 11th, 2012, 12:31am:hello Yawei,
-ve group delay is little bit new to me, i know for some filters it will be fine, but i haven't seen any real channels with this behavior. Please double check once. Double check with s parameters.
Regarding your group delay impact on link performance, normally if ripple in the group delay is less than 10% of bit period then there is not much impact (according to sakinger book), in reality if you limit less than 6% it will be really good and you don't see any data dependent jitter. In your plot ripple is around 1ps, which is acceptable even at 5Gbps (here tb=200ps, so 10% ripple 20ps ).
Thanks,
Raj.