Magnetic Recording Current Waveform Control for Bit Error Reduction
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Solution Overview
Problem
As magnetic recording density increases, bit error rate (BER) deterioration occurs due to inappropriate recording current adjustments in pattern-dependent write (PDW) methods, leading to recording pattern missing issues.
Innovation Solution
A magnetic recording apparatus with a controller that adjusts the recording current waveform based on first and second current parameters, specifically using different overshoot currents, phase adjustments, and base currents at discontinuity points in the recording bit sequence to optimize the recording current waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If recording current is increased to improve recording density, then recording density increases, but bit error rate deteriorates due to inappropriate current adjustment
Solution Approach 1:
The patent applies different recording current waveforms (first current waveform and second current waveform) to different recording patterns. Specifically, the first current waveform is used for patterns where the kth bit and (k+1)th bit have the same polarity, while the second current waveform is used when they have different polarities. This local differentiation of current characteristics resolves the contradiction by optimizing recording for each pattern type rather than using a uniform current approach.
Solution Approach 2:
The patent changes parameters of the recording current waveform based on the recording pattern. The controller selects between different current waveforms by adjusting parameters such as current amplitude, pulse width, and polarity timing according to the specific bit pattern being recorded. This dynamic parameter adjustment allows the system to maintain high recording density while preventing bit error rate deterioration through pattern-appropriate current optimization.
2Manufacturing precision
If pattern-dependent write method is applied to reduce recording pattern missing, then recording accuracy improves, but bit error rate deteriorates due to inappropriate current adjustment mode
Solution Approach 1:
The patent implements local quality by detecting specific recording patterns (where kth and (k+1)th bits have different polarities) and applying a specialized second current waveform only to those patterns. For all other patterns, the standard first current waveform is used. This targeted approach improves recording accuracy for problematic patterns without introducing errors that would result from applying the same adjustment mode universally.
Solution Approach 2:
The patent employs feedback mechanisms where the controller continuously monitors the recording pattern and dynamically adjusts the current waveform selection accordingly. By detecting the polarity relationship between consecutive bits and responding with the appropriate current waveform, the system achieves both high recording accuracy and maintained reliability through real-time pattern-based feedback control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves bit error rate (BER) performance by effectively managing recording current waveforms at discontinuity points, reducing pattern missing errors and enhancing recording density.
Implementation Method 1
A magnetic recording apparatus includes a magnetic head that records data on a recording medium
Data Source
AI summary
A magnetic recording apparatus in an embodiment includes a magnetic head, a storage, a detector, and a controller. The magnetic head records data on a recording medium. The storage stores first current parameters defining a first current waveform, second current parameters defining a second current waveform, and recording bit sequence information. The detector detects a discontinuity point from the recording bit sequence information. The discontinuity point is defined by a position at which recording bit lengths are discontinuous. The controller controls a waveform of a recording current of the magnetic head, based on the first current parameters at a recording bit that is not next to the discontinuity point and based on the second current parameters at a recording bit that is next to the discontinuity point.