Patent ID: 7203884

Claim:
A magnetic recording technique having an improved encoding ratio comprising: providing an input digital signal; converting the digital signal between a non-encoded form (x i ) and an encoded form (a i ) via Matched Spectral Null (MSN) block encoding where, in the encoded form, the signal is arranged in blocks of symbols (a i ), the symbols of each block defining a running digital sum (RDS) value, defined as RDS([a 0 a 1 . . . a N−1 ])=−Σ i (−1) a i wherein the symbols a i belong to the set { 0 , 1 } and the sum extends for values of i from 0 to N−1, with blocks of symbols with a given length (L) used for MSN coding, wherein RDS=RDS 0 +4K, where K is an integer, RDS is the said running digital sum, RDS 0 is defined as zero for even values of the said length (L), and one for odd values of said length (L), and wherein the process represents a state space that corresponds to the parity of the encoded signal; driving a write head with the digital signal in encoded form; and writing the digital signal in encoded form on magnetic recording media via a magnetic recording technique.