The VLBA Sensitivity Upgrade Project

J.D. Romney, W.F. Brisken, S.J. Durand, and R.C. Walker (NRAO)

The VLBA Sensitivity Upgrade Project primarily targets a nearly sixfold increase in continuum sensitivity, expanding the entire data path, downstream from the IFs, to 4-Gbps bandwidth. The upgrade includes a new sampler-filter "digital backend" that replaces the existing analog baseband conversion and sampling scheme, a wider-band version of the Mark 5 disk-based recording system, and a flexible software correlator. The new equipment could be operational next year, with throughput then limited only by available recording and correlation processing capacity, allowing operation at 4-Gbps peak rate much earlier than the 2011 project goal, for the most scientifically compelling observations.