Patent ID: 8228972

Claim:
A method, comprising: transmitting from a first device a data pattern over a first branch of a communications link toward a second device; perturbing a signal communicating the data pattern over the first branch using a controlled insertion of jitter; receiving at the first device a looping back of the data pattern by the second device over a second branch of the communications link; determining by the first device a bit error rate of the looped back data pattern, wherein said inserted jitter causes an increase in the determined bit error rate; and adjusting a pre-emphasis applied to the transmitted data pattern over the first branch in response to the determined bit error rate; wherein adjusting the pre-emphasis comprises adjusting the pre-emphasis applied to the transmitted data pattern over the first branch so as to effectuate a reduction in the increased bit error rate that is present in the looped back data pattern at the first device due to said controlled insertion of jitter that is perturbing the signal communicating the data pattern over the first branch.