Distributed Time Synchronization Protocol for Asynchronous Systems
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Solution Overview
Problem
Conventional distributed time synchronization protocols for asynchronous communication systems require an independent physical link for synchronization, leading to increased cost and weight, and suffer from timing errors due to propagation delays among slave devices.
Innovation Solution
A protocol that uses the communication bus for both data transfer and time synchronization, where the master node defines a packet interval, maximum payload size, and baud rate to ensure deterministic communication, and measures propagation delays to correct timing errors among slave nodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an independent physical link dedicated to time synchronization is used, then time synchronization accuracy is improved, but system cost and weight increase
Solution Approach 1:
The patent merges the time synchronization function with the existing data communication bus, eliminating the need for a separate physical synchronization link. The master node transmits both data and synchronization information through the same communication medium, reducing system complexity, cost, and weight while maintaining synchronization capability.
Solution Approach 2:
The communication bus is designed to serve multiple functions simultaneously: data transmission and time synchronization. By making the synchronization protocol compatible with the existing data communication infrastructure, the system achieves multi-functionality without requiring additional dedicated hardware links.
2Measurement precision
If an independent physical link for synchronization is used, then time synchronization is achieved, but propagation delay errors among slave devices increase
Solution Approach 1:
The patent implements a feedback mechanism where the master node measures the propagation delay to each slave device by analyzing the timing of received packets. The master then uses this measured delay information to calculate and apply compensation values, adjusting the synchronization timing to account for individual cable length differences and propagate delay variations.
Solution Approach 2:
The system dynamically adjusts synchronization parameters based on measured propagation delays. By changing the timing offset parameters for each slave device according to its specific distance from the master, the system compensates for cable length variations and achieves accurate synchronization across the network.
3Device complexity
If the communication bus is used for both data transfer and synchronization, then system complexity is reduced, but deterministic communication timing becomes more difficult to ensure
Solution Approach 1:
The patent segments the communication protocol into distinct phases and packet types, with specific packets dedicated to synchronization purposes. By structuring the communication bus traffic with defined timing relationships and separating synchronization data from general data traffic, the system maintains deterministic timing characteristics while sharing the bus for multiple functions.
Data Source
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AI summary
A master node of a distributed acquisition system is provided. The master node includes a communication interface for interfacing between a control component and a bus and the control component. The bus is coupled to one or more slave nodes distributed in the acquisition system. The control component is configured to acquire a configuration that provides a definition for a packet interval, wherein the packet interval definition provides an adequate timing margin to ensure that communication packets transmitted by the master node and the one or more slave nodes occur only at harmonics of the packet interval definition, distribute a time reference packet of the communication packets based on the packet interval definition via the bus to all of the slave nodes of the distributed acquisition system, and schedule transmission of communication packets transmitted by the master node via the bus to the one or more selected slave nodes based on the packet interval definition.