The ASKAP digital signal processing system will be made up of a suite of special purpose data converters, beamformers and a correlator. This system will combine the signals received by each antenna into a format that can be processed into radio images and spectral cubes to produce the astronomer's 'result' from ASKAP.
Each ASKAP antenna will have a digital beamformer which will take in approximately 188 IF signals from ASKAP’s receivers, each of 300 MHz bandwidth. These will be digitised and processed by a first stage polyphase filterbank. The data generated will then be transported on a separate signal and data transport system to the beamformer. The beamformer will process this data to generate up to 36 beams, with the data for each beam channelised to a resolution suitable for spectroscopic observing.
The beamformed data will then be transported to a correlator which forms the cross-power spectrum for the signals for each pair of antennas on each of the beams. The output from the correlator will then go to ASKAP’s computing system, which will also provide control signals and monitor the operation of the correlator.
The compute load in the filterbanks, beamformers and correlator will be about 2 petaflops. This will be computed on a data stream that totals 70 Tb/s.
The team implementing the digital signal processing system has prototyped much of the design in existing systems with which they have been involved. These systems include the wide-band spectrometer for CSIRO’s Mopra telescope at Coonabarabran, the Compact Array Broadband Backend 2 GHz correlator for the Australia Telescope Compact Array at Narrabri, the 384-input correlator for the SKA Molonglo Prototype, the correlator for the Murchison Widefield Array radio telescope, and a 48-input beamformer (upgradable to a 192-input beamformer) for the Parkes Testbed Facility.
Opportunities for Industry
Information on opportunities for industry to be involved in the development of ASKAP can be found on the industry page.