Class of PARTIAL RESPONSE Systems for Increasing Storage Density in Magnetic Recording
Original Publication Date: 1989-Aug-01
Included in the Prior Art Database: 2005-Jan-28
In a digital magnetic recording channel, the density of magnetic transitions on the medium and the width of the readback pulse are related to the achievable linear density for a given head, disk, and flying height combination. Pulse-slimming equalizer and/or run-length limiting codes are commonly used for increasing linear density. More recently, the class IV partial response technique (PR4) has been investigated. However, the width of the readback pulse, equalized for the PR4 channel, is about the same as that in the case of (1,7) code for a given net linear density. Higher linear density with PR4 will require further equalization. This equalization, in general, results in loss of signal-noise ratio.