Disk Storage Head Position Demodulation via Dynamic Gate Signal Width
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Solution Overview
Problem
Conventional disk storage devices face limitations in seek operation response performance due to demodulation errors caused by increased head velocity during radial movement, which reach a demodulation limit velocity, obscuring the correspondence between decoded and real positions.
Innovation Solution
The disk storage device employs a servo pattern with position signals recorded in a recording area, using a signal generator to produce timing signals with shorter periods and shifted centers for improved demodulation, allowing the controller to adjust the head's position more accurately during seek operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the head velocity is increased to improve seek operation response performance, then the seek speed is improved, but the demodulation precision deteriorates due to demodulation errors
Solution Approach 1:
The gate signal width is dynamically adjusted based on the head velocity during seek operations. When the head velocity exceeds a predetermined threshold, the gate signal width is reduced to a shorter period, allowing the system to maintain accurate position demodulation at higher velocities by adapting the measurement window to the increased speed conditions.
Solution Approach 2:
The system changes the parameter of gate signal width based on operating conditions. By switching between different gate signal widths (normal width for low velocity, shorter width for high velocity), the system optimizes the balance between demodulation accuracy and response performance across different seek operation scenarios.
2Measurement precision
If the gate signal width is kept at normal width for accurate demodulation, then the measurement precision is maintained, but the response performance deteriorates at high head velocities
Solution Approach 1:
The gate signal width is dynamically adjusted based on the head velocity during seek operations. When the head velocity exceeds a predetermined threshold, the gate signal width is reduced to a shorter period, allowing the system to maintain accurate position demodulation at higher velocities by adapting the measurement window to the increased speed conditions.
Solution Approach 2:
The system changes the parameter of gate signal width based on operating conditions. By switching between different gate signal widths (normal width for low velocity, shorter width for high velocity), the system optimizes the balance between demodulation accuracy and response performance across different seek operation scenarios.
Data Source
AI summary
According to one embodiment, a disk storage device includes: a disk on which a servo pattern is recorded; a head; a driver; a signal generator; a demodulator; and a controller. Position signals for detecting an offset position from a center of a track are recorded in a recording area of a servo pattern. The signal generator generates a first timing signal indicating a timing for reading the position signals. When the controller performs a seek operation for moving the head to a target track, the signal generator generates a second timing signal. The period of the second timing signal for reading each of the position signals is made shorter than that of the first timing signal. A center time of the period of the second timing signal is shifted closer to a demodulation center time corresponding to a center of the recording area than that of the first timing signal.