paper

A 6-12 GHz Analogue Lag-Correlator for Radio Interferometry

arXiv:astro-ph/0701644 · doi:10.1051/0004-6361:20066879

Abstract

Aims: We describe a 6-12 GHz analogue correlator that has been developed for use in radio interferometers. Methods: We use a lag-correlator technique to synthesis eight complex spectral channels. Two schemes were considered for sampling the cross-correlation function, using either real or complex correlations, and we developed prototypes for both of them. We opted for the ``add and square'' detection scheme using Schottky diodes over the more commonly used active multipliers because the stability of the device is less critical. Results: We encountered an unexpected problem, in that there were errors in the lag spacings of up to ten percent of the unit spacing. To overcome this, we developed a calibration method using astronomical sources which corrects the effects of the non-uniform sampling as well as gain error and dispersion in the correlator.

arXiv comment14 pages, 21 figures, accepted for publication in A&A

References in corpus (4)

Cited by in corpus (9)