Stochastic flash ADC in hardware correlator for very long baseline interferometry

Abstract

© 2018 IEEE. Very long base interferometry uses the network of radio telescopes for measuring signals from distant spacecraft and extra-galactic radio sources. Hardware correlator is the main processing unit for collected data, used to determine signal amplitude, baseline, geometric delay, fringe phase, signal source position, etc. Stochastic flash Analog to Digital Converter uses dithering signal with uniform distribution of the probability density. It is the basis of Stochastic Measurement Instrument that can be used for quantization of received data with main benefits of having high precision dependent on the length of measurement period (below 1 ppm for 6 hour measurement), simple topology with small number of components and few sources of systematic error. This enables low-cost but high-precision and fast multichannel hardware VLBI correlator to be built.