The Hat Creek millimeter-wave hybrid spectrometer for interferometry

Abstract

A hybrid analog-digital spectrometer has been built and is installed at Hat Creek Observatory on the millimeter-wave interferometer (Welch et al. 1977). The analog portion of the instrument comprises the filters; the digital part consists of a three-level correlator. The correlator serves three baselines, providing 512 complex channels for each. The bandwidth of the digital portion of the correlator is 40 MHz. The correlator may be partitioned in a flexible way, so that each part is fed by one sideband of a filtered portion of the band; in this way a total bandwidth of 320 MHz may be achieved. Other configurations are possible.