A SCALABLE HYBRID FPGA/GPU FX CORRELATOR

Abstract

Radio astronomical imaging arrays comprising large numbers of antennas, O(10 2 –10 3 ), have posed a signal processing challenge because of the required O (N 2 ) cross correlation of signals from each antenna and requisite signal routing. This motivated the implementation of a Packetized Correlator architecture that applies Field Programmable Gate Arrays (FPGAs) to the O (N) "F-stage" transforming time domain to frequency domain data, and Graphics Processing Units (GPUs) to the O (N 2 ) "X-stage" performing an outer product among spectra for each antenna. The design is readily scalable to at least O(10 3 ) antennas. Fringes, visibility amplitudes and sky image results obtained during field testing are presented.