Seagate Technology Incorporated

Chandra Chuda Varanasi

Kinhing Paul Tsang

Dennis C Stone

Leroy Allen Volz

Nersi Nazari

A method and apparatus are provided for decoding a sequence of code words into a sequence of data words. Each code word includes an encoded data word and an indicator bit. The encoded data word is extracted unchanged into a respective unencoded data word if an indicator bit has a first binary value and is extracted into the unencoded data word and then complemented if the indicator bit has a second, opposite binary value.

DC-free code having limited error propagation and limited complexity

A method and apparatus are provided for encoding and decoding digital information. A sequence of data words is received, wherein each data word has a running digital sum (RDS). The sequence of data words is encoded into a sequence of corresponding code words, which has a current RDS. For each data word a binary symbol is added to the data word and the data word is selectively complemented as a function of the RDS of the data word and the current RDS of the sequence of code words to form the corresponding code word.

Systems and methods that encode and decode data in a manner that limits error propagation by parsing a data word of length n into a predetermined number of data blocks, individually encoding each data block into a single associated code block, and then combining each of the code blocks to form a resulting code word of length (n&plus;1), resulting in a code rate of n/(n&plus;1). By parsing and encoding the data word in this manner, errors that occur with respect to one or more bits of one code block will not be propagated throughout an entire data word during the decoding process.

Run length limited coding with minimal error propagation

Rate n(n+1) code for embedded servo address encoding

The present invention involves a method to transmit data over a communication channel that can be modelled as one of the three following partial response channels: dicode channel, PR4 channel and EPR4 channel. The method includes choosing a code, based on its algebraic structure, to obtain a desired minimum distance for the coded channel. A data sequence to be written to the storage medium is received and encoded according to the chosen code, to obtain encoded data. The encoded data is written to the storage medium.

Coding data in a disc drive according to a code having desired algebraic

A method is provided for encoding and decoding binary data, using a non-quasicatastrophic and phase invariant matched spectral null code for a partial response channel. The method is particularly suited for partial response systems wherein the order of the higher order null in the transfer function of the partial response channel is .gtoreq.1, resulting in signal-to-noise (SNR) gain at the channel output. In a preferred form, the method is used to develop a rate 3/10 Nyquist-null trellis code.

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Longmont, CO, United States of America

Chandra Chuda Varanasi