|Description:|| The picture above shows our three firmware engineers in a mildly excited state. They have been developing the APERTIF digital beamformer. All the accumulated tension, built up during the last working day of 2012, was released after they successfully demonstrated a working beamformer at full speed (200 MHz), from beginning to end.|
In the test, a digital waveform generator was used as input of 64 signal paths (emulating 64 antennas). This signal was filtered by the digital filterbank which splits up the input bandwidth in 512 subbands. Accordingly subbands of each antenna are selected by a subband selector. Multiple subsets of the subbands for all antennas are transported to the beamformer nodes. Each beamformer node deals with one subset of 24 subbands and calculates on average 40 beams from the 64 input antennas. In total, 16 beamformer nodes are used for one polarization of one telescope. To this end, four UniBoards are integrated in a subrack. The described test involved all four UniBoards.
From left to right: Daniel van der Schuur, Harm-Jan Pepping and Eric Kooistra