Asymmetrical Secondary Read Elements for Magnetic Head Noise Reduction
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Solution Overview
Problem
As data tracks on magnetic media become closer, adjacent track signals cause significant unwanted signal noise, making it challenging to read data tracks at high track pitch with existing magnetic recording systems.
Innovation Solution
A magnetic read head with a primary read element and secondary read elements having asymmetrical cross-track amplitude profiles, where the secondary read elements are laterally offset and have steeper outer edges and broader inner edges, allowing them to selectively pick up signals from adjacent tracks without picking up noise from further tracks, which are then subtracted from the primary read signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If data tracks are placed closer together to increase data density, then storage capacity increases, but adjacent track interference causes increased signal noise
Solution Approach 1:
The read head is segmented into multiple independent read elements (primary and secondary) positioned at different lateral locations. Each element reads from a different track, allowing the system to separate and process signals from adjacent tracks independently, then combine them to eliminate interference
Solution Approach 2:
The secondary read elements are designed with asymmetrical cross-track amplitude profiles, having steeper amplitude decay on one side and broader profile on the other side. This asymmetry allows selective pickup of signals from specific adjacent tracks while minimizing pickup from further tracks, enabling effective interference cancellation
2Productivity
If the functional track width is made smaller than the physical width of the read element to achieve high track pitch, then track density increases, but signals from adjacent tracks become unwanted noise
Solution Approach 1:
The read head is divided into multiple read elements positioned at different lateral locations to read from different tracks simultaneously. This segmentation allows the system to functionally narrow the effective track width by combining signals from multiple elements, achieving high track pitch while maintaining signal accuracy through digital signal processing
Solution Approach 2:
The system uses feedback through signal processing where signals from secondary read elements are subtracted from the primary read element signal. This feedback mechanism eliminates adjacent track interference from the final output, maintaining measurement precision even when functional track width is smaller than physical read element width
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 configuration results in a more accurate signal with reduced noise, enabling higher data density and track pitch by effectively eliminating signal interference from adjacent tracks.
Implementation Method 1
A magnetoresistive sensor such as a Giant Magnetoresistive (GMR) sensor can be employed to read a magnetic signal from the magnetic media
Implementation Method 2
A magnetoresistive sensor such as a Giant Magnetoresistive (GMR) sensor or a Tunnel Junction Magnetoresistive (TMR) sensor
Implementation Method 3
When current flows through the coil, a resulting magnetic field causes a magnetic flux to flow through the coil, which results in a magnetic write field emitting from the tip of the write pole
Data Source
AI summary
A magnetic read head configured for two dimensional magnetic recording and having asymmetrical secondary read elements. The magnetic read head includes a primary read element configured to read a data track (i.e. n data track) and first and second secondary read elements located over adjacent data tracks (i.e. n+1, n−1 data track) at either side of the data track to be read. The secondary read element have asymmetrical off track amplitude profiles, preferably such that they each have a steep amplitude profile at the outer side and a broader cross-track amplitude profile at their inner sides. This allows the secondary read elements to detect signals of the adjacent data track (so that those signals can be subtracted out of the signal from the primary reader) without the secondary read elements also picking up further adjacent data tracks (i.e. n+2, n−2).