6.11 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 baseband channels; rates available are 32, 16, 8, 4, or 2 Msamples per second on each channel; for spectral-line observations at channel widths narrower than 1 MHz, oversampling is necessary. This subsection will become obsolete when the new digital backends are installed on the VLBA later in 2010. See the beginning of Section 6 for further information.