Correction Parameter Calculation for Clock Synchronization
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Solution Overview
Problem
Existing time synchronization systems face challenges in accurately synchronizing clocks across a network due to fluctuating propagation time intervals and quartz oscillation frequency errors, making it difficult to maintain precise timing in applications like factory automation.
Innovation Solution
A correction parameter calculation device that calculates a speed ratio between main and subordinate clocks based on measured transmission and reception time points, allowing for accurate synchronization even when propagation time intervals are not constant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the shortest propagation time communication is selected to eliminate fluctuation, then propagation time stability is improved, but measurement precision deteriorates because even the shortest communication still includes fluctuation
Solution Approach 1:
The patent segments the propagation time measurement into multiple individual communication events and analyzes each separately. By dividing the total measurement into discrete communication instances, the system can identify and exclude abnormal values while retaining valid data points, thus resolving the contradiction between stability and precision.
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors propagation time across multiple communications, compares measured values against expected ranges, and adjusts the correction parameter calculation accordingly. This feedback loop enables the system to compensate for fluctuations and maintain both stability and precision.
2Measurement precision
If multiple communications are performed to calculate mean values, then measurement precision is improved, but loss of time increases due to repeated communication cycles
Solution Approach 1:
The patent applies partial action by performing a limited number of communication cycles (exactly two-way communications) rather than continuous or excessive measurements. This optimized approach calculates mean propagation time and standard deviation from a sufficient but not excessive sample size, achieving the required precision while minimizing time loss.
Solution Approach 2:
The patent changes the parameter from performing multiple sequential one-way communications to performing fewer two-way communications. This parameter change in the communication protocol efficiency allows the system to obtain the necessary statistical data (mean and standard deviation) with fewer overall communication events, reducing time loss while maintaining precision.
3Stability of the object's composition
If propagation time fluctuation is suppressed by selecting specific communications, then stability is improved, but device complexity increases due to additional selection logic
Solution Approach 1:
The patent applies self-service by enabling the system to automatically identify and handle abnormal propagation time values through statistical analysis. The communication selection mechanism uses simple criteria (values outside mean ± standard deviation range) that the system can evaluate autonomously without complex external control logic, thus improving stability while limiting complexity.
Data Source
AI summary
Even if the propagation time interval of a sync signal is not constant, an accurate correction parameter is calculated, so that a corrected time point synchronized with a main clock device is obtained. A main transmission time point storage part stores respective main transmission time points at which a main device has transmitted a plurality of main sync signals and which are measured using a main clock device. A subordinate reception time point storage part stores respective subordinate reception time points at which a subordinate device has received the plurality of main sync signals and which are measured using a subordinate clock device. A speed ratio calculation part calculates a speed ratio of a ticking time speed of the main clock device to a ticking time speed of the subordinate clock device, based on a main transmission mean time point being a mean of the main transmission time points and a subordinate reception mean time point being a mean of the subordinate reception time points.