The University of British Columbia

Data-dependent jitter (DDJ) occurs when transmitting high-speed serial data signals through physical transmission medium. In test applications, the DDJ due to the test fixture and measurement equipment may be significant relative to the jitter under measurement. To avoid the loss of accuracy, special calibration methodologies are required to reduce the DDJ impact from test fixtures. This paper describes a novel technique for DDJ calibration for cases where signal pulse shape does not vary significantly from DUT to DUT. This method uses the signal history prior to each transition to estimate the test fixture induced DDJ and compensates for it regardless of data pattern or bit rate. We also introduce a new technique for separating the DDJ due to long-term history (in long transmission lines) from that of the short-term history preceding a transition