A method for bit error rate testing a processing unit using a bit error rate tester (BERT) includes transmitting a signal pair to a receiver of the processing unit, the signal pair having jitter levels complying with a jitter threshold, tuning the signal pair to obtain a first stressed eye measurement for the receiver, wherein the first stressed eye measurement complies with a stressed eye mask, placing the processing unit into a loop-back mode, wherein data transmitted to the processing unit by the BERT is transmitted back to the BERT, transmitting a data pattern to the processing unit, receiving a looped back version of the data pattern from the processing unit, and calculating a bit error rate in accordance with the data pattern and the looped back version of the data pattern.