White Rabbit同步技术是传统PTP(IEEE1588v2)协议的扩展,增加了皮秒级时间戳、频率相位同步、稳定传输时延等功能,在时频/数据一体化传输方面性能卓越。针对White Rabbit在时间敏感领域的应用现状,归纳了时间频率传递、精准时间戳标记...White Rabbit同步技术是传统PTP(IEEE1588v2)协议的扩展,增加了皮秒级时间戳、频率相位同步、稳定传输时延等功能,在时频/数据一体化传输方面性能卓越。针对White Rabbit在时间敏感领域的应用现状,归纳了时间频率传递、精准时间戳标记、射频信号分布传输、定时触发控制等应用方式,详细介绍了各类具体应用的实现方法和性能指标。通过分析当前采用的增强手段和未来发展趋势,展望该技术在各领域广泛的应用前景。展开更多
You may still remember the story about the race between the big white rabbit and little tortoise, in which the over-proud rabbit lost. However, the White Rabbit toffees produced by the Shanghai Guansheng Yuan (Group) ...You may still remember the story about the race between the big white rabbit and little tortoise, in which the over-proud rabbit lost. However, the White Rabbit toffees produced by the Shanghai Guansheng Yuan (Group) Co., Ltd. are famous-brand products in China. This White Rabbit not only is the cham-展开更多
Due to the large scale of Water Cherenkov Detector Array in Large High Altitude Air Shower Observatory, the frontend digitization is imperative.Thus a clock distribution system is desired,which broadcasts the synchron...Due to the large scale of Water Cherenkov Detector Array in Large High Altitude Air Shower Observatory, the frontend digitization is imperative.Thus a clock distribution system is desired,which broadcasts the synchronous clock signals with low jitter to the frontend electronics distributed in the field of 90 000 m^2.The White Rabbit protocol provides an option,which has been approved to achieve sub-ns accuracy and ps jitter in the synchronization of around 1 000 nodes in the order of 10 km.But the hierarchy of the original is too complex for Large High Altitude Air Shower Observatory application.Thus we proposed a reduced scheme based on the White Rabbit protocol.The validation circuit shows that the clock skew due to the fiber length difference can be adjusted to less than 25 ps and the clock jitter is less than 62 ps.展开更多
We demonstrate a new synchronization method for the White Rabbit system. Signals are transmitted in a single mode fiber in both directions with the same light wavelength. Without the complex calibration process of the...We demonstrate a new synchronization method for the White Rabbit system. Signals are transmitted in a single mode fiber in both directions with the same light wavelength. Without the complex calibration process of the fiber asymmetry parameter, the new method reduces the effect of chromatic dispersion and improves the synchronization accuracy. The experiment achieves timing synchronization accuracy below 200 ps over 50 km fiber constructed by different companies＇ fiber spools. The proposed method would make White Rabbit technology immune to the chromatic dispersion of fiber links and can be applied to long distance synchronization.展开更多
Background White Rabbit(WR)is a deterministic Ethernet-based network for general-purpose data transfer and subnanosecond time synchronization in large distributed systems.WR has been used in Large Hadron Collider and ...Background White Rabbit(WR)is a deterministic Ethernet-based network for general-purpose data transfer and subnanosecond time synchronization in large distributed systems.WR has been used in Large Hadron Collider and Large High-Altitude Air Shower Observatory for physics experiment.Purpose WR mainly uses the optical fiber for data transmission between WR devices.Commercial off-the-shelf Direct Attach Cable is not suitable for WR network at 100m level distance.Considering the lower cost of Category(CAT)Ethernet cable compared to optical fiber and the demand of remote power supply in distributed system at 100m level length,we developed a novel transmission scheme with CAT Ethernet cable for WR.Methods The novel transmission scheme uses the CAT Ethernet cable and small form-factor pluggable connector which is compatible with the optical links.This scheme only uses two pairs of twisted lines in the CAT Ethernet cable for data uplink and downlink.The other two pairs of twisted lines are used for remote power supply.Results and conclusion The novel transmission scheme could use the CAT Ethernet cable to complete remote power supply and time synchronization with expected time offset of less than 100 ps and standard deviation of less than 20 ps in the WR distributed system.The distance of distributed nodes could be 80m with one CAT 7 Ethernet cable or 150m with relay transceiver connecting two CAT 7 Ethernet cables.In the short-distance scenarios,the novel transmission scheme has lower cost than the optical fiber and additional power supply function.展开更多
The open reading frame （ORF） of hAPOA1 was inserted into the prokaryotic expression vector pGEX-4T-1 to construct the recombinant plasmid pGEX- 4T-I-hAPOA1, which was then transformed into Escherichia coil strain BL...The open reading frame （ORF） of hAPOA1 was inserted into the prokaryotic expression vector pGEX-4T-1 to construct the recombinant plasmid pGEX- 4T-I-hAPOA1, which was then transformed into Escherichia coil strain BL21. The expression of target fusion protein was induced with isopropyl β-D-l-thiogalacto- pyranoside （IPTG）. The purified fusion protein in inclusion bodies was used to immunize New Zealand white rabbits to prepare hAPOA1 antiserum and the antibody titer was detected with indirect enzyme-linked immunosorbent assay （ID-EL1SA）. ID-ELISA and Western Blot proved that rabbit polyclonal antibody with a high titer of 1 ： 40 000 was produced, which may bring considerable economic benefits.展开更多
文摘You may still remember the story about the race between the big white rabbit and little tortoise, in which the over-proud rabbit lost. However, the White Rabbit toffees produced by the Shanghai Guansheng Yuan (Group) Co., Ltd. are famous-brand products in China. This White Rabbit not only is the cham-
基金Supported by the National Natural Science Foundation of China(No.11175174 and No.11005107)the Knowledge Innovation Program of the Chinese Academy of Sciences(KJCX2-YW-N27)
文摘Due to the large scale of Water Cherenkov Detector Array in Large High Altitude Air Shower Observatory, the frontend digitization is imperative.Thus a clock distribution system is desired,which broadcasts the synchronous clock signals with low jitter to the frontend electronics distributed in the field of 90 000 m^2.The White Rabbit protocol provides an option,which has been approved to achieve sub-ns accuracy and ps jitter in the synchronization of around 1 000 nodes in the order of 10 km.But the hierarchy of the original is too complex for Large High Altitude Air Shower Observatory application.Thus we proposed a reduced scheme based on the White Rabbit protocol.The validation circuit shows that the clock skew due to the fiber length difference can be adjusted to less than 25 ps and the clock jitter is less than 62 ps.
基金supported by the Program of International S&T Cooperation under Grant No.2016YFE0100200
文摘We demonstrate a new synchronization method for the White Rabbit system. Signals are transmitted in a single mode fiber in both directions with the same light wavelength. Without the complex calibration process of the fiber asymmetry parameter, the new method reduces the effect of chromatic dispersion and improves the synchronization accuracy. The experiment achieves timing synchronization accuracy below 200 ps over 50 km fiber constructed by different companies＇ fiber spools. The proposed method would make White Rabbit technology immune to the chromatic dispersion of fiber links and can be applied to long distance synchronization.
基金the State Key Laboratory of Particle Detection and Electronics,SKLPDE-ZZ-201918.
文摘Background White Rabbit(WR)is a deterministic Ethernet-based network for general-purpose data transfer and subnanosecond time synchronization in large distributed systems.WR has been used in Large Hadron Collider and Large High-Altitude Air Shower Observatory for physics experiment.Purpose WR mainly uses the optical fiber for data transmission between WR devices.Commercial off-the-shelf Direct Attach Cable is not suitable for WR network at 100m level distance.Considering the lower cost of Category(CAT)Ethernet cable compared to optical fiber and the demand of remote power supply in distributed system at 100m level length,we developed a novel transmission scheme with CAT Ethernet cable for WR.Methods The novel transmission scheme uses the CAT Ethernet cable and small form-factor pluggable connector which is compatible with the optical links.This scheme only uses two pairs of twisted lines in the CAT Ethernet cable for data uplink and downlink.The other two pairs of twisted lines are used for remote power supply.Results and conclusion The novel transmission scheme could use the CAT Ethernet cable to complete remote power supply and time synchronization with expected time offset of less than 100 ps and standard deviation of less than 20 ps in the WR distributed system.The distance of distributed nodes could be 80m with one CAT 7 Ethernet cable or 150m with relay transceiver connecting two CAT 7 Ethernet cables.In the short-distance scenarios,the novel transmission scheme has lower cost than the optical fiber and additional power supply function.
基金Supported by the Agricultural Science Independent Innovation Fund Jiangsu Province[CX(16)1326]
文摘The open reading frame （ORF） of hAPOA1 was inserted into the prokaryotic expression vector pGEX-4T-1 to construct the recombinant plasmid pGEX- 4T-I-hAPOA1, which was then transformed into Escherichia coil strain BL21. The expression of target fusion protein was induced with isopropyl β-D-l-thiogalacto- pyranoside （IPTG）. The purified fusion protein in inclusion bodies was used to immunize New Zealand white rabbits to prepare hAPOA1 antiserum and the antibody titer was detected with indirect enzyme-linked immunosorbent assay （ID-EL1SA）. ID-ELISA and Western Blot proved that rabbit polyclonal antibody with a high titer of 1 ： 40 000 was produced, which may bring considerable economic benefits.
