Wideband Observing

by Stephan W. Witz last modified Jul 08, 2012 by Stephan Witz

The wideband observing setup provides the widest possible bandwidth for a given observing band, with channel spacing depending on the number of polarization products.

Wideband & Subarray Correlator Options
Polarization products Channel spacing
Full (RR, RL, LR, LL) 2   MHz
Dual (RR, LL) 1   MHz
Single (RR or LL) 0.5 MHz

For the low-frequency bands (L, S, C, X, and Ku bands) this uses the 8-bit samplers to provide a total of 2 GHz of bandwidth per polarization. The three highest-frequency bands (K, Ka, and Q bands) employ the new 3-bit (wideband) samplers, providing a total of 8 GHz of bandwidth; in this case all subbands are 128 MHz wide. In many frequency bands the total processed bandwidth is less than that delivered by the front-end. In those cases the observer may independently tune two 1 GHz baseband pairs when using the 8-bit samplers, or four 2 GHz baseband pairs when using the 3-bit samplers. The (fairly mild) tuning restrictions are described in the section on VLA Frequency Bands and Tunability.