Understanding single-ended and mixed-mode S-parameters

Differential circuits provide noise-free signal transmission in communicati ons, In the past, these circuits have been associated with low-frequency sy stems. At relatively low frequencies, these circuits can be designed and an alyzed using lumped-element models and techniques. But when differential ci rcuits are applied to systems operating beyond 1 GHz (and equivalently 1 Gb /s in digital communications systems) this lumped-element approach is no lo nger valid;