Skew Compensation in Patterned Media Using Angular Offsets
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Solution Overview
Problem
Existing patterned media technologies face challenges in maintaining uniform bit intervals and compensating for transducer skew, which leads to non-uniform data presentation and increased intersymbol interference, due to limitations in self-assembly processes and mechanical configurations.
Innovation Solution
The implementation of a rotatable substrate with hypertracks arranged into concentric zones, where each row of data recording dots is angularly offset to compensate for transducer skew, using a twist angle to align timing fields with a virtual stroke path, and arranging servo fields along the mechanical stroke path to prevent collisions and maintain phase coherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If rows of data recording dots are arranged in conventional circular tracks, then the medium is easier to manufacture, but transducer skew causes non-uniform bit intervals and increased intersymbol interference
Solution Approach 1:
The patent divides the circular track into multiple linear rows of dots that are angularly offset from each other. Instead of using a continuous circular track, the data is segmented into discrete linear rows that collectively form the track structure, allowing skew compensation while maintaining manufacturing feasibility
Solution Approach 2:
The patent introduces angular offsets between adjacent rows of dots, creating an asymmetric pattern that compensates for transducer skew. This asymmetric arrangement ensures uniform bit intervals despite the skewed transducer position, resolving the contradiction between manufacturing simplicity and precision
2Reliability
If timing fields are made continuous across zones, then phase coherence is maintained, but collisions occur at zone boundaries affecting system performance
Solution Approach 1:
The patent divides the timing field into discrete segments located at specific radial positions within each zone. Instead of a continuous timing field, segmented timing fields are provided that avoid collisions at zone boundaries while maintaining phase coherence through angular positioning and synchronization
Solution Approach 2:
The patent resolves the collision problem by transitioning from a radial continuity approach to an angular positioning approach. Timing fields are positioned in the angular dimension at specific locations within zones, allowing phase coherence to be maintained through angular relationships rather than radial continuity
3Manufacturing precision
If a single pivot point is used for the actuator, then the mechanical structure is simpler, but skew angle varies across the stroke path reducing data retrieval consistency
Solution Approach 1:
The patent applies different angular offsets to different rows of dots based on their specific radial positions and local skew conditions. Each row is locally optimized with an angular offset tailored to its position, ensuring uniform data presentation across the entire stroke path while using a simple single-pivot actuator structure
Data Source
AI summary
Apparatus for providing skew compensation in a patterned medium, such as but not limited to a self-assembling bit patterned medium. In accordance with some embodiments, the apparatus includes a transducer and a rotatable substrate. The substrate has a plurality of rows of spaced apart data recording dots. Each row of dots is angularly offset from an immediately adjacent row responsive to a skew angle of the transducer. The rows of dots are arranged into concentric zones of hypertracks. Each zone has an arcuate timing field segment which extends across the zone and is angularly discontinuous with the timing field segment of an immediately adjacent zone.