Magnetic Tape Servo Pattern Edge Shape and Spacing Control
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Solution Overview
Problem
Magnetic tape apparatuses face challenges in maintaining high reproducing quality due to the relative position changes between reading elements and tracks, leading to signal interference and decreased recording capacity.
Innovation Solution
A magnetic tape with a timing-based servo pattern and a spacing difference measured before and after ethanol cleaning, optimized for improved edge shape accuracy and reduced positional deviations, is used in conjunction with a reading element unit that performs waveform equalization using a two-dimensional FIR filter to enhance data extraction from multiple reading elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the recording track width is narrowed to increase recording capacity, then the recording capacity increases, but the reproducing quality deteriorates due to signal mixing from adjacent tracks
Solution Approach 1:
The invention divides the reading function into multiple reading elements arranged in a matrix configuration, where each element reads signals from specific tracks. This segmentation allows selective reading from the target track while excluding adjacent tracks, thereby maintaining high reproducing quality even when track width is narrowed to increase recording capacity.
Solution Approach 2:
The invention transitions from a single reading element to a two-dimensional matrix array of reading elements. This dimensional expansion enables selective activation of specific reading elements corresponding to the target track, allowing precise signal extraction while rejecting interference from adjacent tracks, thus resolving the contradiction between narrow track width and reproducing quality.
2Measurement precision
If multiple reading elements are used to improve reproducing quality by reading the target track signal, then the reproducing quality improves, but the device complexity increases
Solution Approach 1:
The reading element matrix is designed to serve multiple functions: it can selectively read from any track by activating appropriate elements, perform interference rejection, and adapt to different reading positions. This multi-functionality reduces the need for separate dedicated components for each function, thereby managing device complexity while achieving high reproducing quality.
Solution Approach 2:
The invention employs dynamic control of reading element selection based on the target track position. By dynamically activating only the necessary reading elements corresponding to the current reading position, the system achieves high reproducing quality without permanently maintaining complex hardware configurations for all possible reading scenarios.
3Device complexity
If a sliding type magnetic tape apparatus is used for data reading, then the apparatus structure is simple, but the relative position between reading element and target track changes during reproducing, deteriorating reproducing quality
Solution Approach 1:
The invention incorporates feedback mechanisms that continuously monitor the position of the magnetic tape relative to the reading element matrix. Based on this feedback, the system dynamically adjusts which reading elements are activated to compensate for position changes, thereby maintaining stable reproducing quality despite the sliding apparatus structure.
Solution Approach 2:
The invention changes the operational parameters of the reading element matrix based on detected position variations. By adjusting which elements are active and their weighting factors in real-time, the system compensates for relative position changes during sliding, maintaining consistent reproducing quality without requiring a completely different apparatus structure.
Data Source
AI summary
The magnetic tape includes a non-magnetic support and a magnetic layer, in which an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference between a value L99.9 of a cumulative distribution function of 99.9% and a value L0.1 of a cumulative distribution function of 0.1% in a position deviation width from an ideal shape of the magnetic tape in a longitudinal direction is 180 nm or less, and in which a difference between a spacing Safter measured on a surface of the magnetic layer by an optical interferometry after ethanol cleaning and a spacing Sbefore measured on the surface of the magnetic layer by an optical interferometry before ethanol cleaning is greater than 0 nm and 6.0 nm or less.