Ternary Pattern Dependent Write Signaling for Magnetic Recording
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Solution Overview
Problem
Magnetic recording systems face challenges in efficiently controlling write current characteristics due to the non-linear relationship between write current and magnetization state, leading to insufficient magnetic saturation during closely-spaced transitions and delayed magnetic response, which affects recording quality and areal density.
Innovation Solution
Implementing pattern-dependent write signaling using ternary or multi-level pulse-amplitude modulated signals to communicate magnet lengths from a write data circuit to a preamplifier, allowing dynamic adjustment of write current parameters based on data patterns, specifically controlling overshoot amplitude and duration to improve recording quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If write current is increased to achieve magnetic saturation during closely-spaced transitions, then magnetic saturation is improved, but write head switching speed decreases due to non-linear relationship
Solution Approach 1:
The patent applies dynamics by making the write current characteristics variable rather than fixed. The system dynamically adjusts write current parameters including amplitude, duration, and timing based on detected data patterns. This allows the write head to receive optimized current pulses that achieve magnetic saturation when needed while maintaining fast switching speed, resolving the contradiction between reliability and speed.
Solution Approach 2:
The patent changes physical parameters of the write current including amplitude, duration, and timing based on data patterns. By varying these parameters dynamically, the system achieves magnetic saturation during closely-spaced transitions when required while maintaining overall switching speed, thus resolving the contradiction between magnetic saturation reliability and switching speed.
2Manufacturing precision
If pattern-dependent write signaling is implemented to control write current characteristics, then recording quality is improved, but device complexity increases
Solution Approach 1:
The system uses the existing write data pattern information to automatically control write current characteristics without requiring separate control signals. The write data circuit detects patterns in the data itself and uses this information to adjust write current parameters, making the system self-regulating and reducing overall complexity despite the advanced control capability.
Solution Approach 2:
The write data circuit performs multiple functions: it processes write data for recording, detects data patterns, and generates control signals for write current characteristics. By making the write data circuit multi-functional, the patent improves recording quality without adding separate dedicated control circuitry, thus limiting the increase in device complexity.
3Productivity
If ternary signaling is used to communicate magnet lengths, then signaling efficiency is improved, but noise immunity requirements increase
Solution Approach 1:
The system uses feedback by detecting data patterns in the write data and using this information to control write current characteristics. This feedback mechanism allows the system to achieve efficient ternary signaling while compensating for noise through pattern-based control, as the system can adapt to actual data conditions rather than relying solely on signal strength.
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 enhances recording quality and bit-error-rate by dynamically varying write current characteristics according to data patterns, improving areal density and reducing the need for explicit signaling of boost levels, while relaxing timing requirements and reducing noise immunity issues.
Implementation Method 1
Data to be recorded is provided to the write head coil as an alternating electrical current. The electrical current passes through a metallic coil wrapping around the write head, generating a magnetic field.
Implementation Method 2
As the magnetized pole tip is passed over the magnetic storage medium, for example a spinning ferromagnetic platter, the magnetization of regions of the magnetic medium below the pole tip are altered
Data Source
AI summary
A storage system includes a magnetic write head, a magnetic storage medium, a write data circuit having a write data output and a magnet length signal output, and a preamplifier that receives the write data and a magnet length signal from the write data circuit, and sets at least one write current characteristic through the magnetic write head based at least in part on the magnet length signal. The write data circuit processes write data to be recorded on the magnetic storage medium by the magnetic write head. The magnet length signal output communicates magnet lengths in the write data.