Patent ID: 7158060
Filing Date: 2007-01-02
Classification: G11B,H03M

Abstract:
1. A modulation apparatus for converting data into variable length strings of channel bits that are NRZI representations of logical code words in which d is a minimum run length and k is a maximum run length limit of ‘0’ bits, said modulation apparatus having conversion means for converting input data into code in accordance with a conversion table wherein said conversion table enforces a conversion rule, according to which the remainder of division of a ‘1’ count of an element in a data string by 2 having a value of 0 or 1 shall always be equal to the remainder of division of a ‘1’ count of an element in the string of code words resulting from conversion of said data string by 2 and conversion codes of said conversion table comprise: basic codes; first substitution codes used when the basic codes fail to maintain the minimum run length d; and second substitution codes used when the basic codes fail to maintain the maximum run length limit k.