Phase Locked Clock Module for Coherent Servo Writing
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Solution Overview
Problem
Existing data storage technologies face inefficiencies in writing servo patterns across multiple zones with different frequencies, leading to increased manufacturing time and costs due to the need for multiple writing steps and potential phase excursions during clock frequency changes.
Innovation Solution
A phase locked clock (PLC) module synchronizes multiple servo clocks to a reference clock, allowing for coherent writing with a single frequency phase across servo zones with different frequencies, eliminating the need for temporary servo patterns and reducing manufacturing overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple writing steps are used to write servo patterns across multiple zones with different frequencies, then the servo patterns can be written accurately for each zone, but the manufacturing time increases and costs increase
Solution Approach 1:
The patent combines multiple writing operations into a single coherent writing operation. By using a single frequency phase reference that is coherent across all servo zones, the system can write servo patterns for multiple zones simultaneously in one operation, eliminating the need for multiple separate writing steps and thereby reducing manufacturing time while maintaining accuracy
Solution Approach 2:
The single frequency phase reference serves multiple functions across different servo zones. Instead of requiring separate reference signals for each zone, the system uses one universal reference that works across all zones with different frequencies, enabling multi-functional operation and improving productivity
2Adaptability or versatility
If clock frequency changes are made during servo zone transitions, then the system can adapt to different frequency zones, but phase excursions occur during the transition
Solution Approach 1:
The system performs preliminary synchronization of the write clock to the read clock before the actual writing operation. By establishing phase coherence in advance through synchronization mechanisms, the system prepares the clock signals to maintain phase alignment during zone transitions, preventing phase excursions and ensuring reliable operation across frequency zones
Solution Approach 2:
The system uses feedback mechanisms to monitor and adjust clock phase relationships. By continuously monitoring the phase difference between write and read clocks and making real-time adjustments, the system maintains phase coherence during transitions and adapts to different frequency zones without introducing phase excursions
3Reliability
If temporary servo patterns are used during the writing process, then the system can maintain phase coherence during transitions, but the manufacturing overhead increases
Solution Approach 1:
The patent extracts and eliminates the need for temporary servo patterns from the writing process. By using a single frequency phase reference that is inherently coherent across all zones, the system removes the requirement for temporary patterns that would otherwise be needed to maintain phase coherence during transitions, thereby reducing manufacturing overhead and complexity
Data Source
AI summary
Systems and methods are disclosed for phase locking of a clock. In some embodiments, a phase locked clock (PLC) module can phase-lock a write clock to a media written with multiple servo zones of different frequencies. In some implementations, this can be utilized to perform a self-servo write (SSW) of a disc surface within a hard disc drive (HDD). A PLC module can perform a method of writing with a single frequency phase coherently while a read element passes over servo zones with different frequencies. While the PLC module can perform such methods for a SSW process, the methods can also be utilized for other applications that can benefit from writing with a single frequency phase coherently based on servo zones with different frequencies.