Correladores en banda base para un interferómetro de gran formato a 30 GHz

Abstract

The aim of the reported work is to explore the viability of a correlator for a future large-scale interferometer, with hundreds of receivers, by developing a pathfinder in which the 30 GHz receivers of QUIJOTE experiment will be reused. Nowadays, there are some interferometric experiments designed to study the Cosmic Microwave Background (CMB). Although the sensitivity of the instruments is proportional to the number of receivers, interferometers normally present a reduced number of them due to the difficulty to correlate a large number of wide-band signals. For this reason, thinking about a Michelson-type interferometer, two types of single base-line correlators are proposed in order to compare them and to analyse their viability. The first choice is an analog correlator designed on FR4 substrate with a 10 kHz video bandwidth. The maximum frequency of the correlator input signals should not exceed 300MHz. On the other hand, a digital version has been implemented using a PCI card from Agilent Technologies with a maximum digitalization rate of 1GS/s on each of its two inputs.