FPGA-based digital signal processing for radio astronomy

Field Programmable Gate Arrays (FPGA) are a novel way to process astronomical signals, improving performance of radio astronomy receivers beyond state-of-the-art. FPGA technology has also a wide range of applications to other areas of engineering. In the Millimeter-wave Laboratory (MWL), the area of digital back-ends has been very active both in generating new data with our home-built digital sideband separating receivers, and in developing a digital polarization receiver. Digital sideband separation on a fully assembled receiver for ALMA Band 9 (without removing the IF hybrid) was achieved on mid-2016, showing that this technique could be applied to already operative 2SB receivers without front-end modifications with a digitally calibrated receiver exhibiting cross-polarization performance 10 to 15 dB better than their purely-analog counterpart. The MWL is part of a new initiative called “ALMA Digital Front-End: Configurations Study” that aims to establish a working group which will specifically consist of front-end, back-end and system experts from major ALMA partners and JAO who will consider advanced front-end/back-end configurations.