CPL - Chalmers Publication Library
| Utbildning | Forskning | Styrkeområden | Om Chalmers | In English In English Ej inloggad.

TIME TRANSFER USING AN ASYNCHRONOUS COMPUTER NETWORK: RESULTS FROM A 500 KM BASELINE EXPERIMENT

Sven-Christian Ebenhag (Institutionen för mikroteknologi och nanovetenskap, Fotonik) ; R. T. Kenneth Jaldehag ; Per O. J. Jarlemark ; Per Olof Hedekvist (Institutionen för mikroteknologi och nanovetenskap, Fotonik) ; T. Ragne Emardson ; Peter Löthberg
Topical Meeting on Precise Time and Time Interval, 27-30/11, Long Beach, CA (2007)
[Konferensbidrag, refereegranskat]

SP Technical Research Institute of Sweden and STUPI have performed a time transfer experiment over a 500km long baseline between Borås and Stockholm. The time transfer technique passively utilizes the data bit stream generated in an optical fiber computer network based on the packet over SONET/SDH technique. A small fraction of the optical signal is monitored both at the transmitter and at the receiver. When an occurrence of a unique bit sequence of the SDH frames is detected, an electrical pulse is generated and compared with a resolution of 100 ps to a local clock. With data from all four positions of an optical bidirectional link, two-way time-transfer can be achieved and any symmetrical variations in delay can potentially be cancelled. The results presented here have been obtained over OptoSUNET, the new Swedish University Network. In the experiment, 10 Gbit/s traffic from SP over OptoSUNET is extended in Stockholm to STUPI, a clock laboratory which is the second node in this setup. This reconnection enables that a communication channel is established between two nodes, with no intermediate jump. The time-transfer experiment includes more than 500 km of fiber transmission, of which several km is via air-lines. By comparing the results from a GPS carrierphase link, a precision better than ± 1 ns is achieved over several months of measurements between two Hydrogen-masers.



Denna post skapades 2008-01-17.
CPL Pubid: 67251