Coding in Magnetic Channels at Rates Higher Than Unity
Original Publication Date: 1986-Feb-01
Included in the Prior Art Database: 2005-Mar-08
For a set I of channel inputs (i) and corresponding outputs 0(i), let X be any set of inputs which when added together form another input, designated Sum(X). The channel is defined as linear over I if, for every X, the output associated with Sum(X) is the sum of all the outputs associated with the members of X; or (Image Omitted) Empirically, modern data channels are linear over the set of two level inputs. A PR4 channel is one such ,which, when sampled at appropriate frequency and phase, and after appropriate amplification, yields samples of: .... 0 0 1 0 -1 0 0 ... when fed with input that is in one sense for all except one clock interval, which input is termed an isolated unit pulse.