James Broomall, Senior Signal Integrity Engineer, W.L. Gore & Associates, Inc.
Christopher Ericksen, Signal Integrity Engineer, W.L. Gore & Associates, Inc.

At 1 Gbps the bit unit interval is 1000 ps, but at 10 Gbps it is only 100 ps. Pair skew of 100 ps might be perfectly acceptable at 1 Gbps, but at 10 Gbps, this amount of skew will cause complete conversion of the signal from differential to common mode. Whether the differential transmission line is a twin-axial cable or PCB trace pair, determining the differential skew is necessary for ensuring signal integrity. This presentation will explore methods for making meaningful measurements of differential skew as well as relationships between time domain and frequency domain differential transmission line performance.