By Peter McMahon, RTCC Student at CASPER and Dr Alan Langman, Sub-system Manager DSP, MeerKAT project

The collaboration between the MeerKAT Digital Backend (DBE) team and the Center for Astronomy Signal Processing and Electronics Research (CASPER) at the University of California (UC), Berkeley, is producing its first results less than six months after the project started in earnest.

The DBE team is currently using CASPER's iBOB hardware and software design tools and libraries to build a system for processing signals from the MeerKAT prototype dish. The teams are also working together to develop cutting edge instruments for future radio telescopes.

The CASPER team works closely with the Radio Astronomy Laboratory (RAL) in the Department of Astronomy at UC, Berkeley, who are building the Allen Telescope Array (ATA). This contact with the ATA project and other telescope projects around the world, including MeerKAT, ensures that CASPER continues to work on important projects that are of broad interest to digital back-end designers working on current and future radio telescopes.

The present generation iBOB board from CASPER, and the next-generation hardware ROACH (Reconfigurable Open Architecture Computing Hardware), are both designed specifically for digital processing of signals in radio telescopes. ROACH, currently under development through a collaboration of MeerKAT, CASPER and the NRAO (National Radio Astronomy Observatory in the USA), is set to deliver more than half a Teraop of processing power and up to four bidirectional 10 Gbit communication links. ROACH will provide the primary building block for digital signal processing systems in numerous next generation radio telescopes.

Skills development is essential for the success of MeerKAT. Currently the DBE team has two postgraduate electrical engineering students, both from the University of Cape Town, as year-long visitors at Berkeley. Jason Manley is working on building a 32-station dual polarization correlator. This is a key instrument in an array-based radio telescope such as MeerKAT, which essentially combines the signals from multiple antennas in such a way that a single image of the sky can be formed from its output. Peter McMahon is working on building a so-called "pulsar back-end" that MeerKAT will need to be able to search for and characterize pulsars. Peter is also working with other CASPER and MeerKAT engineers on high-level designs of possible architectures for high bandwidth correlators built using ROACH boards.

The South African MeerKAT project derives great benefit from this access to the engineers and scientists at CASPER, but also deliver benefits to its international partners. Dave George from the DSP team has already ported a much-needed driver for 10 Gigabit Ethernet for the iBOB to the CASPER library, while the work done by Francois Kapp as the lead design engineer on the ROACH board is crucial for its development. Jason and Peter's work will also certainly be useful to a variety of CASPER's partners, including NRAO at Green Bank and the ATA as well as for MeerKAT. Based on the successes and promise shown from the first six months of collaboration, we are looking forward to further collaboration with the CASPER team.

Left: Peter McMahon (front) and Jason Manley (back) working in the labs at the Berkeley Wireless Research Center. Right: Marc Welz, MeerKAT Lead Firmware Engineer, holding iBOB hardware in front of the DBE XDM rack.