Magnetic Storage Medium Preamble Phase Detection
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Solution Overview
Problem
Conventional magnetic storage devices face challenges in achieving high recording density and accurate magnetic head positioning due to track oscillation and limited servo areas, which deteriorate device performance and reduce recording density.
Innovation Solution
A magnetic storage medium with a magnetic recording layer comprising a servo area, two preamble areas with staggered magnetic bodies, and a re-sync mark area, along with a phase difference detector and displacement calculator to accurately position the magnetic head using phase differences from the preamble areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of servo areas per track is increased to increase the amount of servo information to be sampled, then the servo control band is increased and positioning precision is improved, but the data areas decrease and recording density per unit area is lowered
Solution Approach 1:
The magnetic recording medium is segmented into distinct functional areas: servo areas for positioning, preamble areas for timing synchronization, and data areas for user information. This segmentation allows each area to be optimized for its specific function without compromising the others, resolving the contradiction between servo area size and data area availability.
Solution Approach 2:
The patent introduces a temporal dimension by using preamble areas with specific magnetic dot arrangements that generate timing signals. This allows positioning and timing functions to be separated in the time domain, enabling accurate head positioning without requiring excessive servo area space, thus maintaining recording density.
2Measurement precision
If feedforward control is performed based on detected track oscillation to improve positioning precision, then positioning accuracy is improved, but the process of investigating track oscillation needs to be executed in advance and device performance deteriorates due to repeated confirmations
Solution Approach 1:
The patent performs preliminary action by writing reference signals and establishing feedforward control parameters during the initial formatting stage. This preliminary setup captures track oscillation characteristics once, and the control system uses these pre-established parameters for continuous positioning correction without needing repeated investigations, thereby maintaining high device performance while achieving accurate positioning.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the reproduced reference signal amplitude variations to detect track oscillation in real-time. This feedback mechanism allows the system to dynamically adjust head positioning without requiring repeated preliminary investigations, resolving the contradiction between positioning accuracy and device performance.
3Device complexity
If the magnetic head is positioned using only servo pattern information, then the positioning process is simple, but track oscillation causes the magnetic head to be inaccurately positioned
Solution Approach 1:
The patent introduces an intermediary reference signal written in the data recording track that serves as a mediator between the servo system and the actual magnetic head position. This reference signal allows the system to detect track oscillation effects and apply corrections without fundamentally complicating the positioning process architecture, achieving accurate positioning while maintaining relative simplicity.
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 solution enables high-precision positioning control of the magnetic head, improving recording density and maintaining device performance by accurately detecting and correcting head displacement, even under disturbances like temperature changes.
Implementation Method 1
a magnetic head configured to read and write data with respect to the magnetic storage medium
Implementation Method 2
a phase difference detector configured to acquire output of the preamble areas by the magnetic head, and detect phase difference from the readout signal of the preamble areas
Data Source
AI summary
According to one embodiment, a magnetic storage medium, includes a magnetic recording layer that includes: a servo area including predetermined servo information; a user data area including predetermined user information; two preamble areas including a plurality of magnetic bodies made of magnetic particles, the magnetic bodies being arranged in a staggered pattern so that the staggered pattern is inverted with respect to an axis of symmetry at a track center; and a re-sync mark area positioned at a head of the preamble areas and indicates a start of the preamble areas.