Orthogonal Preamble Read Head Deviation Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In magnetic recording systems, as areal densities increase, data tracks are written in an overlapping fashion, making it crucial to determine the degree of off-track deviation of read heads to maintain optimal performance, as existing technologies lack effective methods to accurately detect and correct such deviations.
Innovation Solution
The method involves writing data tracks with orthogonal preambles and using a read head to detect signals from both tracks, applying a Discrete Fourier Transform to the preamble output to determine the off-track ratio, utilizing read circuitry with Discrete Fourier Transform circuits and computation circuitry to calculate the off-track deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If areal densities are increased by writing data tracks in an overlapping fashion, then storage capacity is improved, but the ability to accurately detect read head position deteriorates
Solution Approach 1:
The preamble on each track is segmented into orthogonal components (e.g., even tracks use one orthogonal pattern, odd tracks use another). This segmentation allows the system to distinguish between adjacent tracks by detecting which orthogonal component is present, thereby maintaining position detection accuracy despite track overlap
Solution Approach 2:
The patent changes the parameter of the preamble signal by using orthogonal patterns for different tracks. By varying the orthogonal component parameter based on track identity, the system can determine read head position accurately even when tracks overlap, as each track's orthogonal signature can be independently detected
2Quantity of substance
If read head dimensions are reduced to match track width in high-density systems, then storage density is improved, but the difficulty of detecting off-track deviation increases
Solution Approach 1:
The system uses feedback by analyzing the orthogonal components of the detected preamble signal. By comparing the detected orthogonal component against known patterns for different tracks, the system generates feedback information about the read head's position, enabling accurate off-track deviation detection even with dimensionally matched read heads
Solution Approach 2:
The patent employs parameter changes in the signal domain by utilizing orthogonal components with distinct characteristics. This allows the system to extract position information from the signal parameters rather than relying solely on physical read head dimensions, thereby maintaining detection capability in high-density configurations
Data Source
AI summary
A storage device includes read circuitry having a read head having a detector that outputs signals representing data from a first track and an adjacent track. The read head is subject to off-track excursions during which the read head detects signals from both the first track and an adjacent track. Data on each track includes a preamble including a repeating pattern. The repeating pattern in any first track is orthogonal to the repeating pattern in any track adjacent to the first track. The read circuitry also includes respective Discrete Fourier Transform circuits to identify components in the signals corresponding to respective frequencies characteristic of the repeating pattern on the first track and the repeating pattern on the second track, and computation circuitry to determine from the components a ratio by which the read head is off-track. Corresponding methods are provided for operating such a storage device and for reading data.