Joint Equalizer Coefficient Adaptation for Track Misregistration
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Solution Overview
Problem
Current magnetic recording technologies like BPMR and HAMR require costly modifications to media and heads, and TDMR relies heavily on powerful signal processing, while ARMR aims to increase areal density with an array-reader and associated signal processing to mitigate track misregistration (TMR) effects.
Innovation Solution
The method involves determining an estimated off-track condition, selecting translation coefficients, updating equalizer coefficients, and applying them to signals from an array-reader to output a read signal, which can be implemented in a TDMR read circuit as part of an integrated circuit to improve read performance in magnetic disk systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If BPMR or HAMR is used to increase recording density, then areal density is improved, but manufacturing cost significantly increases due to required modifications to media and heads
Solution Approach 1:
The patent uses multiple read heads to read the same track simultaneously and creates a virtual copy of the track data through signal processing. This allows conventional media and heads to achieve high areal density without physical modifications, avoiding the high manufacturing costs of BPMR and HAMR while maintaining improved recording density through software-based solution
2Quantity of substance
If TDMR is used to achieve high bit-per-grain recording density, then areal density is improved, but device complexity increases due to reliance on powerful signal processing
Solution Approach 1:
The patent divides the read signal into multiple components by using multiple read heads positioned at different locations. Each head reads a portion of the track, and the signals are segmented and processed independently before being combined. This segmentation reduces the complexity of individual processing operations while achieving high recording density through parallel reading
Solution Approach 2:
The patent transitions from single-head sequential reading to multi-head parallel reading, adding a spatial dimension to the reading process. By reading multiple tracks simultaneously with multiple heads and using joint signal processing, the system achieves high areal density without requiring excessively complex signal processing for each individual track
3Quantity of substance
If array-reader is used to increase areal density, then recording density is improved, but read performance deteriorates due to track misregistration effects
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors track position and adjusts the read heads' positioning and signal processing parameters in real-time. This feedback loop compensates for track misregistration by adapting the joint equalizer coefficients based on actual read conditions, maintaining high read performance despite variations in track alignment
Solution Approach 2:
The patent dynamically changes the parameters of the joint equalizer based on the estimated off-track condition. When track misregistration is detected, the system adjusts the equalizer coefficients to optimize signal processing for the current misalignment state. This parameter adaptation allows the system to maintain high read performance across varying track positions while achieving high areal density
Data Source
AI summary
A method of mitigating an effect of track misregistration on read performance in a system comprising an array-reader includes determining an estimated off-track condition, selecting translation coefficients based on the estimated off-track condition, determining updated equalizer coefficients by applying the translation coefficients to native equalizer coefficients, and applying the updated equalizer coefficients to signals received from the array-reader to output a read signal.