Multi-Stage MISO Read Circuit for Fast Track Adaptation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multi-input, single-output (MISO) systems in data storage devices face challenges in adapting quickly to changes in reader positioning over data tracks, leading to slower adaptation rates compared to single reader systems, which can result in read failures and increased error correction needs.
Innovation Solution
A multi-stage MISO circuit with a first stage filter having a short number of taps for rapid adaptation during transient events and a second stage filter with more taps for fine-grain adjustments in steady-state conditions, combined with gearing to switch between high and low adaptation step sizes, enables fast adaptation while maintaining high steady-state performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single reader system is used, then adaptation speed is fast, but read reliability is reduced due to positioning errors
Solution Approach 1:
The patent segments the MISO filter into two distinct stages: a first stage with fewer taps for fast adaptation during transient events, and a second stage with more taps for fine-grain adjustments in steady-state. This segmentation allows each stage to be optimized for its specific function, resolving the contradiction between fast adaptation and read reliability by having the first stage quickly correct positioning errors while the second stage maintains precision
Solution Approach 2:
The patent implements dynamic switching between different adaptation step sizes using a gear selector. During transient events, a first adaptation step size is applied for rapid convergence, while during steady-state operation, a second (smaller) adaptation step size is used for fine-grain adjustments. This dynamic adaptation mechanism enables the system to achieve both fast initial adaptation and high steady-state reliability
2Measurement precision
If MISO filter adapts quickly to transient events, then reader positioning accuracy improves, but steady-state noise performance deteriorates
Solution Approach 1:
The patent divides the MISO filter into two stages with different tap counts optimized for different operational conditions. The first stage with fewer taps provides fast adaptation for positioning accuracy during transients, while the second stage with more taps provides noise filtering for steady-state performance. This segmentation resolves the contradiction by assigning different functional priorities to each stage
Solution Approach 2:
The patent changes the adaptation step size parameter dynamically based on operational state. A first (larger) adaptation step size is used during transient events to quickly improve positioning accuracy, while a second (smaller) adaptation step size is used during steady-state to maintain low noise levels. This parameter switching resolves the contradiction between positioning accuracy and noise performance
3Reliability
If a long MISO filter is used, then steady-state performance is high, but adaptation speed to transient events is slow
Solution Approach 1:
The patent segments the filter into a first stage with fewer taps for fast adaptation and a second stage with more taps for high steady-state performance. The first stage can quickly respond to transient events while the second stage maintains excellent steady-state performance, resolving the contradiction between adaptation speed and steady-state performance
Solution Approach 2:
The patent applies different filter characteristics to different stages: the first stage is optimized for fast response with fewer taps, while the second stage is optimized for high performance with more taps. This local optimization of filter properties at different stages resolves the contradiction by allowing each stage to excel at its specific function
Data Source
AI summary
Systems and methods are disclosed for applying multi-stage multiple input single output (MISO) circuits for fast adaptation. An apparatus may comprise a first reader and a second reader configured to simultaneously read from a single track of a data storage medium, a MISO circuit. The MISO circuit may include a first stage filter having a first number of taps and configured to filter signal samples received from the first reader and the second reader and produce first filtered samples. The MISO circuit may also include a second stage filter having a second number of taps greater than the first number, and be configured to receive the first filtered samples corresponding to the first reader and the second reader from the first filter stage, filter the first filtered samples to produce second filtered samples, and combine the second filtered samples to produce a combined sample output.