SAN HEALTH CHECK

An Eye Diagram is an oscilloscope display in which a digital data signal from a receiver is repetitively sampled and applied to the vertical input, while the data rate is used to trigger the horizontal sweep. It is so called because, for several types of coding, the pattern looks like a series of eyes between a pair of rails.

An eye diagram shows the spread of the signal. The more the jitter or the longer the distance the thicker the signal width. Eventually the receiver is unable to detect the edges of the signal.

Modal dispersion is a distortion mechanism occurring in multimode fibers and other waveguides, in which the signal is spread in time because the propagation velocity of the optical signal is not the same for all modes. For instance, central paths travel faster than outer paths.

Other names for this phenomenon include multimode distortion, multimode dispersion, modal distortion, intermodal distortion, intermodal dispersion, and intermodal delay distortion.