Samplers

Samplers convert the analog BBC outputs to digital form. There are two samplers, each of which handles signals from 4 BBCs. Either 1-bit (2-level) or 2-bit (4-level) sampling may be selected. A single sample rate applies to all BB channels; rates available are 32, 16, 8, 4, or 2 Msamples per second on each channel; for spectral-line observations at channel widths smaller than 0.5 MHz, oversampling is required. This subsection will become obsolete when the new digital back ends are installed on the VLBA in 2009.