Differential Pairs The Physics Behind USB PCIe HDMI & DDR Routing

A single trace cannot survive in the noise world above a certain speed. So engineers built something that can. Every high-speed interface on a modern PCB runs as a differential pair: USB, PCIe, HDMI, DDR, SATA, Ethernet. Most designers follow the rules without understanding why they exist. Using Cadence's field solver and Sigrity X Aurora, we cover what a differential pair actually does to signal amplitude, how common mode rejection cancels noise, and why it contains its electromagnetic field in a way a single-ended trace physically cannot.