inter symbol interference (ISI)

Symbol crosstalk, inter symbol interference ( ISI), is a data-dependent jitter (DDJ) in which pulse-shaped light signals are broadened by dispersion during transmission in optical fibers.

Because pulses can be broadened over multiple periods by inter symbol interference, symbol crosstalk limits transmission bandwidth, especially in high bit rate transmissions such as 10 Gigabit Ethernet and 100 Gigabit Ethernet.

The ISI effect can be compensated for using various methods. For example, the Electronic Dispersion Compensation( EDC) and Feed-Forward Equalization (FFE) methods are used for this purpose in various interfaces of 10- gigabit Ethernet. These are realized in the 10GBase-KX4 and 10GBase-KR interfaces, among others, and are implemented in the transceivers.