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

Christian M. Holler·Tak Kaneko·Michael E. Jones·Keith Grainge·Paul Scott
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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.

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Christian M. Holler, Tak Kaneko, Michael E. Jones, Keith Grainge, Paul Scott. 2007-01-23. A 6-12 GHz Analogue Lag-Correlator for Radio Interferometry. https://doi.org/10.1051/0004-6361%3A20066879

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