Development and Performance of the Terminal System for VLBI Space Observatory Programme (VSOP)

Satoru IGUCHI  Noriyuki KAWAGUCHI  Seiji KAMENO  Hideyuki KOBAYASHI  Hitoshi KIUCHI  

IEICE TRANSACTIONS on Communications   Vol.E83-B   No.2   pp.406-413
Publication Date: 2000/02/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electronic and Radio Applications
VLBI,  VSOP,  higher-order sampling,  digital filter,  bandwidth,  phase,  

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The VSOP terminal is a new data-acquisition system for the Very-Long-Baseline Interferometry (VLBI). This terminal was primarily designed for ground telescopes in the VLBI Space Observatory Programme (VSOP). New technologies; higher-order sampling and digital filtering techniques, were introduced in the development. A cassette cart was also introduced, which supports 24-hour unattended operations at the maximum data rate of 256 Mbps. The higher-order sampling and digital filtering techniques achieve flat and constant phase response over bandwidth of 32 MHz without using expensive wide base-band converters. The digital filtering technique also enables a variety of observing modes defined on the VSOP terminal, even with a fixed sampling frequency in an A/D converter. The new terminals are installed at Nobeyama, Kashima, Usuda, Mizusawa, and Kagoshima radio observatories in Japan, and are being used in VSOP and other domestic VLBI observations. In this paper the key features of the VSOP terminal focusing on these advanced technologies are presented, and the results of performance tests are shown.