Adaptive Noise Predictive Filter for Inter-Track Interference Cancellation
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Solution Overview
Problem
In data storage systems, increased bit period density leads to inter-track interference, which diminishes the accuracy of read-back data due to magnetic information interaction between bit periods in one track and surrounding tracks, and existing methods fail to adequately account for this interference.
Innovation Solution
A data processing system is implemented with a first noise predictive filter circuit, a data detector circuit, an inter-track interference cancellation circuit, and an adaptation circuit that generates filter coefficients for a second noise predictive filter circuit based on cleaned data, reducing inter-track interference by correlating read-back signals with side track NRZ data and applying noise predictive filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bit period density is increased to improve storage capacity, then productivity is improved, but inter-track interference increases causing measurement precision to deteriorate
Solution Approach 1:
The patent converts the harmful inter-track interference into a beneficial signal by using the interfering magnetic information from adjacent tracks to adaptively adjust filter coefficients. The interference that was previously degrading data detection accuracy is now utilized to improve the noise predictive filter's ability to cancel interference, thereby maintaining high storage capacity while recovering measurement precision.
Solution Approach 2:
The patent dynamically changes the filter coefficients of the noise predictive filter based on detected inter-track interference characteristics. By adapting parameters (filter coefficients) in response to changing conditions (interference patterns from high-density storage), the system maintains optimal performance despite increased bit period density and associated interference.
2Measurement precision
If noise predictive filtering is applied to reduce interference, then measurement precision is improved, but device complexity increases due to multiple filter circuits and adaptation mechanisms
Solution Approach 1:
The noise predictive filter adapts its own coefficients using the detected inter-track interference signals and cleaned data from the cancellation circuit. The system performs self-adjustment without requiring external intervention or complex manual tuning mechanisms, reducing overall device complexity while maintaining high measurement precision through adaptive filtering.
Solution Approach 2:
The patent implements a feedback loop where the data detector circuit provides detected outputs to the interference cancellation circuit, which in turn provides cleaned data back to the noise predictive filter for coefficient adaptation. This feedback mechanism enables continuous optimization of filter performance while maintaining a relatively simple circuit architecture through iterative self-improvement.
Data Source
AI summary
Systems, methods, devices, circuits for data processing, and more particularly to systems and methods for adapting noise predictive filters for inter-track interference cancellation in a data processing system.