Backend Systems - Perspectives in 2010

摘要

A new technological vision on the future of the VLBI backend area lets us envision a fully digital implementation of what was until now performed in the analog domain. Several advantages can indeed be expected moving the domain's transition point to an earlier stage, at IF frequency instead of at the final base-band. Such a quantum leap can be afforded because of the rapid changes in digital technology that radio observatories continue to look for maintaining their competitive edge. New processing technologies here discussed will make it possible to reconfigure the whole data handling process using digital conversion to base-band and then to fully benefit from the high data rates in new acquisition and data transport systems, while simultaneously improving the reliability and flexibility of the signal path. In addition, a digital representation of the IF and base-band signals will provide the opportunity to correct for various RFI and calibration effects using embedded DSP algorithms. In order to implement these new techniques a number of major modifications are needed at all telescopes for both single-dish and for VLBI operations. Such modifications could greatly enhance the overall sensitivity of the observatories and improve the reliability of operations. The new hardware should comply with the internationally adopted standards for VLBI in order to allow global applications. A further final step we could anticipate is a brief look at a "next" future, after this near future: a trend to move the transition point yet closer to the sky frequency, overlapping with the receiver area.