How Signal Equalization Works for Different Systems
白皮书
Equalization is a signal processing technique used to extend the use of standard flame retardant type-4 (FR4) printed circuit boards (PCBs) to higher data rates. The nonlinear frequency response and loss characteristics of FR4 can destroy signal quality at data rates as low as 3 Gb/s over trace lengths of a few inches. By applying simple corrections the signal quality can be recovered. When the corrections are applied at the transmitter it is called de-emphasis (or pre-emphasis) and when they are applied at the receiver it is called equalization.
This is an introductory article written to help engineers understand the concept of equalization and terms used in the development of emerging technologies that use standard materials (e.g., FR4) for buses and backplanes at ever higher data rates.