High-precision clock distribution and phase automatic compensation system and phase adjusting method thereof

Abstract

The invention discloses a high-precision clock distribution and phase automatic compensation system and a phase adjusting method thereof. The system comprises a clock distribution module (master) and a plurality of front-end electronics nodes (slave). The master distributes clocks to the multiple slaves by using fibers. The master sends the clocks to the slaves by the fibers; after receiving the clocks, the slaves return the clocks to the master again; the master carries out dynamic measurement on the sum of round-trip time of the clocks to obtain uplink and downlink delay time of the clocks and sends measurement results to the slaves; and according to the measurement results, the slaves carries out dynamic phase adjustment on the received clocks, so that phase synchronization of the slaves and the master can be maintained. With the system and method, the phase synchronization precision is improved and a phase adjustment error caused by the temperature change can be reduced.

Description

technical field [0001] The present invention relates to the technical field of high-precision clock distribution synchronization, in particular to a field-programmable-gate-array (FPGA)-based multi-node high-precision clock distribution and phase in a large-scale space (~1km) Automatic compensation system and its phase adjustment method. Background technique [0002] Clock phase synchronization technology was initially widely used in the field of network communication, such as remote billing, whose synchronization accuracy can reach the order of hundreds of milliseconds; IP network packet delay monitoring, whose synchronization accuracy is better than 100 microseconds; LTE-TDD, WiMax-TDD , and the synchronization accuracy reaches the sub-microsecond level. Traditional synchronization methods in the communication field are based on satellite navigation systems such as the Global Positioning System (Global Positioning System, GPS), which can achieve synchronization accuracy o...

AI Technical Summary

Problems solved by technology

A traditional clock distribution method for physical experiments is to use clock links to distribute clocks. For example, the clock system of the Beijing Spectrograph (BESIII) Time-of-Flight Detector (TOF) introduces the RF signal of the accelerator into the VME chassis through an 80m phase-stable optical fiber. The disadvantage of the method is that the clock link is expensive and expensive, and it is often designed according to different environments and needs, and the versatility is not strong

[0004] Another commonly used clock synchronization method is to use GPS for clock distribution. Auger experimented with GPS receivers for frequency and time synchronization, and calibrated the fixed deviation of GPS receivers in the laboratory in advance. At 3000km 2 GPS receivers are installed on 1,600 water Cherenkov detectors, and the time synchronization precision is better than 20ns. The disadvantage of this method is that the GPS receiving system is expensive, and the receivers and cables are sensitive to temperature changes and are susceptible to temperature drift. influences

[0005] There is also a method using microwave and laser technology, which can obtain extremely high precision, such as the XFEL clock system, the pump-probe experiment of the Linac Coherent Light Source (LCLS) in the United States, etc. However, these methods based on high-precision optical control Clock synchronization systems are extremely expensive

[0006] In order to take into account factors such as large-scale space range, high precision, and price, CERN proposed White Rabbit clock phase synchronization technology on the basis of IEEE1588. Difference, DDMTD) to measure the phase difference, using off-chip VCXO for phase adjustment, the accuracy can reach sub-nanoseconds, but its structure is complex, and no measures are taken to reduce the phase adjustment error caused by temperature changes

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