Time Synchronization System with Cyclic Path Switching
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Solution Overview
Problem
The existing time synchronization systems require a one-to-one connection between local devices and remote devices using optical fibers, leading to a significant increase in equipment costs due to the need for multiple local devices to be connected to multiple remote devices.
Innovation Solution
A time synchronization system that includes a local device with a path switching unit to connect multiple remote devices using individual optical fibers, where the local device sequentially switches among the paths in a cyclic order, using a counter unit to store phase differences and a switching table unit to manage path switching, allowing time synchronization with fewer local devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a one-to-one connection between local devices and remote devices is used, then time synchronization accuracy is maintained, but equipment cost increases significantly
Solution Approach 1:
A single local device is designed to serve multiple remote devices through time-division multiplexing. The local device sequentially connects to different remote devices via optical fibers in a cyclic manner, enabling one local device to perform time synchronization functions for multiple remote devices that would traditionally require separate local devices for each connection.
Solution Approach 2:
The local device operates in a periodic cyclic sequence, switching connection paths to different remote devices in a repeated cycle. This periodic path switching allows the single local device to maintain time synchronization with multiple remote devices over time, replacing the need for simultaneous one-to-one connections.
2Reliability
If multiple local devices are connected to multiple remote devices, then time synchronization can be established for each remote device, but the number of required local devices increases
Solution Approach 1:
The local device is designed with multi-functionality to perform time synchronization operations for multiple remote devices. By incorporating path switching capability and cyclic connection management, a single local device can fulfill the roles that would traditionally require multiple separate local devices, each dedicated to a specific remote device.
Solution Approach 2:
The functionality of multiple local devices is merged into a single local device through time-division multiplexing. The path switching unit combines multiple connection paths under one local device, allowing it to sequentially serve different remote devices as if multiple dedicated local devices were present, thereby reducing the total number of local devices required.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the overall equipment cost by enabling time synchronization between a single local device and multiple remote devices, eliminating the need for as many local devices as remote devices, while maintaining accurate phase difference adjustments.
Implementation Method 1
The local device 20 modulates a carrier signal C0 at 10 MHz with a One Pulse Per Second (1PPS: 1 second pulse) signal that pulses every second, and transmits the modulated signal to the remote device 40 via the optical fiber 60
Implementation Method 2
The E/O conversion unit 26 converts the pulse signal P1 after a delay to an optical pulse signal P2
Implementation Method 3
The O/E conversion unit 42 converts the optical pulse signal P2a to an electrical pulse signal P1a
Implementation Method 4
A phase detection unit 22 detects a phase difference φ1 between the carrier signal C0 transmitted to the optical fiber 60 and the carrier signal C0b sent back from the optical fiber 60
Implementation Method 5
The variable delay unit 24 delays the pulse signal P1 and outputs the delayed pulse signal P1
Data Source
AI summary
A local device of a time synchronization system includes a path switching unit that connects respective remote devices using individual optical fibers and switches the respective optical fibers sequentially in a cyclic order, a counter unit, a phase difference memory unit, and a table unit. The counter unit counts a pulse signal P1d demodulated by a PPS demodulation unit to obtain a count value. The phase difference memory unit stores the count value as path information in association with a phase difference detected by a phase detection unit, and outputs the phase difference associated with this path information indicated by the count value to the variable delay unit. When the count value is input, the table unit outputs a path switching signal for switching to the next optical fiber in the cyclic order to the path switching unit and the path switching unit performs switching to the next optical fiber.