Read/Write Channel Asynchronous Demodulation for Head Positioning
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Solution Overview
Problem
Conventional data storage devices face limitations in achieving accurate and efficient head positioning due to the complexity of processing position error signals, which requires substantial calculations and hardware resources, especially in asynchronous demodulation of servo burst signals.
Innovation Solution
The introduction of read/write channel circuitry with an asynchronous demodulation module that generates radial position signals directly from demodulated null burst signals, reducing the burden on the servo control processor and enabling more accurate and faster position error signal generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional servo control processor performs asynchronous PES demodulation, then position error signal can be generated, but processing complexity and hardware resource requirements increase substantially
Solution Approach 1:
The patent extracts the complex asynchronous demodulation function from the servo control processor and implements it in the read/write channel circuitry. This separates the heavy computational burden from the main processor, reducing its complexity while maintaining PES generation accuracy through dedicated hardware implementation of demodulation algorithms.
Solution Approach 2:
The read/write channel circuitry acts as an intermediary between the raw servo burst signals and the servo control processor. It performs preliminary demodulation and signal processing, transforming complex asynchronous signals into processed position information that the processor can handle more efficiently, thereby reducing overall system complexity.
2Measurement precision
If substantial calculations are performed for position error signal generation, then accurate head positioning is achieved, but processing time and computational resources increase
Solution Approach 1:
The patent replaces software-based calculations in the servo control processor with hardware-based demodulation circuitry in the read/write channel. This substitution of computational mechanics with dedicated electronic processing reduces calculation time while maintaining positioning accuracy, as hardware circuits can perform demodulation operations simultaneously and in real-time.
Solution Approach 2:
The read/write channel circuitry performs demodulation and signal processing actions in advance, before the servo control processor needs to generate the final PES. By pre-processing the servo burst signals and extracting position information early in the signal chain, the system reduces the computational burden and time required for final PES generation.
Data Source
AI summary
Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to a corresponding disk surface of the one or more disks; and one or more processing devices. The one or more processing devices comprise read/write circuitry which comprises an asynchronous demodulation module. The asynchronous demodulation module is configured to receive demodulated null burst signals based on the selected head reading servo burst fields of the corresponding disk surface; and output, based on the demodulated null burst signals, a radial position signal, indicative of a radial position of the selected head.