Kashima 34m	Westford 18m

• VLBI Demonstration
  

  Stations:	Kashima 34m(NICT) , and Westford 18m (MIT)
  Radio Sources:	3C84, 3C454.3
  Data Acquisition:	Receiving data from Mark5B, and ADS-2000 sampler via VSI-H interface at each sites Westford and Kashima.
  Observation Mode:	16MHz 2bit 16channel (512Mbps/Stn)
  Data transfer rate:	16MHz 2bit 1channel (32Mbps)

• Network - Shared 1G net and JGN2
  1G Shared network was used for data transfer from Westford to Japan. Data transfer protocol was TCP/IP. Stable data transfer rate of TCP/IP on the shared-net was 32Mbps, then 32Mbps 1 channel of data have extracted and transfered to Japan.
• Distributed Processing -GMPLS
  Optically linked PCs are used for the platform of real-time correlation processing with software correlator. The data processing PCs are located at distant places and connected by optical link organized by GMPLS.
• Software
  Software tools for data distribution and data stream extraction (channel decomposition) servers are newly developed for this demonstration.

  ADS-2000 data sender	Sending data from VSI-interface card to the network
  Channel Decomposer Server	Extracting requested 2bit stream from 32bit parallel VSI-H
  Data Distributor Server	Distributing data to correlator clients

• Result
  We performed real-time e-VLBI demo over the intercontinental baseline (9500km). The observed data at each radio telescopes were transfered to Software correlator working at Tokyo. Due to limited stable link with TCP/IP, we taransfered single channel of data extracted from 32-bit VSI-H data stream in realtime. The frige was succsesfully detected with software correlator in real-time and displayed in a screen at Hiroshima, where JGN2 symposium was held.

  Fringe of 3C84 detected in this demo in real-time

Acknowledgements

JGN2 Symposium e-VLBI Posters