ywguo

Hi Raj.
Since it usually take very long time to test the BER with PRBS, BER is often estimated, calculated with jitter. If the total jitter is not less than one UI, there must me bit decision error. And the total jitter is split into deterministic jitter and random jitter. The deterministic jitter is the flat part in the bathtub curve, and the random jitter is the skirtlike part of the bathtub curve.
Since the random jitter is Gaussian distribution, then the probability of one clock edge outside the limits is calculated with erfc() function. That means the probability of bit error.
1/2×erfc(√2×α)=BER
For example, α=14 for BER=10^{12}. To ensure BER=10^{12}, Total jitter = DJ + 14×RJ must be less than one UI.
Best Regards, Yawei
