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A One‐bit VLBI Recording and Playback System Using Videotape Recorders
Author(s) -
Michelini R. D.
Publication year - 1970
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs005i010p01263
Subject(s) - very long baseline interferometry , instrumentation (computer programming) , computer science , digital recording , magnetic tape , observatory , computer hardware , software portability , remote sensing , physics , geology , operating system , astronomy
A flexible, hybrid very long baseline interferometry (VLBI) instrumentation system, which uses videotape recorders for recording digitized data, has been developed for making routine observations for geodetic and geophysical measurements. The system records data on videotape in the field and later generates conventional digital magnetic tapes for programed correlation in a high‐speed, general‐purpose computer. By selection of an appropriate data rate, these tapes can be made compatible with the present National Radio Astronomy Observatory‐Arecibo Ionospheric Observatory (NRAO‐AIO) Mk 1 format. In addition, the major components have been designed and chosen so that they can be incorporated into the Mk 2 system now being developed at NRAO. This is a high‐density, wide‐bandwidth system that uses direct videotape correlation. Other more immediate advantages of using videotape recorders are: low initial cost, low cost per bit, long recording time, portability, and minimization of the field installation. This paper describes the entire instrumentation back end, including the video converter, recording system, and computer‐compatible reformatting units. Station timekeeping, which is integral with the recording format, is also discussed.