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Modifying Run-Length-Limited Codes for Recording

IP.com Disclosure Number: IPCOM000037001D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Schneider, RC: AUTHOR [+2]

Abstract

A run-length-limited (RLL) code, used in various devices, is dynamically changed during recording on a recording medium for enhancing the recording operation without altering the operation of the other various devices.

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Modifying Run-Length-Limited Codes for Recording

A run-length-limited (RLL) code, used in various devices, is dynamically changed during recording on a recording medium for enhancing the recording operation without altering the operation of the other various devices.

Unconstrained source data (NRZ or NRZI) is encoded into the RLL code, such as a 0,3 d,k code. The modifier circuit maintains the 0,3 constraints but dynamically changes the code groups for changing the code words to meet different criteria while maintaining the represented information. Upon readback of signals from the recording medium, a decoder for the RLL code first decodes the recorded codewords followed by a modifier decoder for converting the RLL decoded words into correct data.

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