Dual Clock Communication Apparatus for Accurate Packet Staying Time Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In Precision Time Protocol (PTP) systems, communication apparatuses face challenges in accurately measuring the staying time of time synchronization packets due to clock corrections, leading to inaccurate time synchronization between devices.
Innovation Solution
A communication apparatus is designed with two clocks, where one clock is used for time synchronization with a time server (OC function) and the other for measuring packet staying times (TC function), allowing accurate calculation of staying times even during clock adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single clock is used for both time synchronization (OC function) and packet staying time measurement (TC function), then device complexity is reduced, but measurement precision deteriorates due to clock corrections causing discontinuous incrementing
Solution Approach 1:
The patent divides the clock function into two separate clocks: a first clock (PHC) dedicated to time synchronization with the time server, and a second clock dedicated to measuring packet staying times. This segmentation prevents the second clock from being affected by corrections to the first clock, thereby maintaining continuous and accurate incrementing for staying time measurements while keeping each clock's function specialized and manageable.
Solution Approach 2:
The patent assigns different quality characteristics to each clock based on its specific function. The first clock is optimized for time synchronization accuracy with the time server, while the second clock is optimized for continuous, uninterrupted incrementing to accurately measure packet staying times. This local quality approach ensures each clock operates at its optimal performance level for its designated purpose.
2Reliability
If clock correction is performed to maintain time synchronization accuracy, then time synchronization reliability is improved, but staying time measurement accuracy deteriorates due to discontinuous incrementing during correction
Solution Approach 1:
The patent segments the timekeeping functions into two independent clocks, allowing the first clock to undergo corrections for maintaining time synchronization reliability with the time server, while the second clock remains unaffected and continues to accurately measure packet staying times without discontinuous incrementing.
Solution Approach 2:
The second clock acts as an intermediary timekeeping mechanism that indirectly supports the time synchronization system by providing accurate staying time measurements, while being isolated from the direct correction processes applied to the first clock. This intermediary role resolves the conflict between needing corrections for reliability and avoiding disruptions to measurement accuracy.
Data Source
AI summary
A communication apparatus including a first clock and a second clock which operate according to a predetermined time synchronization protocol synchronizes time of the first clock with the time of a time source device, and measures a staying time, in the communication apparatus, of a packet to be transferred to a second communication apparatus or the time source device, with consideration of the time of the second clock.