On Signal Processing and Coding for Digital Magnetic Storage Systems
This thesis is concerned with signal processing and coding algorithms for digital magnetic storage. The generalized magnetic storage channel is explained, whereas both longitudinal and perpendicular recording are treated. Partial-response equalization and detection techniques are presented. Channel coding for this generalized channel comprises error-control coding and constrained coding.
In particular, generalized error-locating coding as well as parity-based postprocessing are presented as possibilities. For modified concatenation of constrained coding and error-control coding, an algorithm utilizing bit flipping is proposed to ensure the constraints.
Finally, it is shown how generalized error-locating codes can be applied to digital magnetic storage channels. The codes and the corresponding decoding algorithms are adapted to the error structure of the channel. Example code constructions are given for different channel properties. Compared to Reed-Solomon codes, gains between 0.1 and 0.5 dB can be observed in all situations that are investigated.