Codes for Improved Timing Recovery in Pr4 and Epr4 Magnetic Recording
نویسندگان
چکیده
RECORDING Steven W. McLaughlin1, Patrick Lee2, and Robert Cloke2 1School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332 2 Western Digital Corporation, 863 Rue Ferrari, San Jose, CA 95138. ABSTRACT We consider an alternative to the widely-used (0; G=I) constraint in partial response digital magnetic recording systems. The new one-pairs constraint is an upper bound on the maximum number of symbols between pairs of ones in a coded sequence. Codes for the one-pairs constraint can be used to limit quasicatastrophic error propagation and improve timing recovery in Class-IV partial response (PR4) and Extended PR4 (EPR4) magnetic recording systems. Rate 4:5, 8:9, 16:17, and 24:25 block and nite state codes are discussed and compared with well-known rate 8:9 and 16:17 block codes. The new codes have improved one pairs statistics, low complexity, and for the 24:25 code, reduced error propagation.
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