Evaluating Intra-Pair Skew in High-Speed Digital Interfaces

As data rates increase, shorter unit intervals make high-speed digital interfaces increasingly sensitive to timing differences between positive and negative signals. This intra-pair skew can distort differential signals, reduce eye openings, and increase bit error rates, making accurate evaluation critical to maintaining signal integrity.

This white paper examines intra-pair skew in both the time and frequency domains and presents a method for precisely introducing and measuring skew using dual PAM4 pulse pattern generators. Test results demonstrate how skew affects BER at PCIe 6.0 data rates and examine the additional effects of sinusoidal jitter, differential mode interference, and different test patterns.

What you’ll learn:

• Why increasing data rates make systems more susceptible to intra-pair skew
• How skew affects differential signals, eye openings, and BER
• How skew can be precisely introduced and controlled for evaluation
• How jitter, interference, and pattern sensitivity influence BER measurements
• How intra-pair skew evaluation can help quantify its impact on PCIe 6.0 system margins