| The digital beamformer for Apertif is taking shape. It consists of eight ADUs (Analog to Digital converter Units), four UniBoard digital processing units, a PAC (Power And Clock distribution) and an AUB (ADU-to-UniBoard Backplane).
For this demonstration, three kinds of test signals simulate the signals from 64 antennas: wide-band (WB) and band-limited (BL) noise, and a CW signal of 719 MHz. The sequence of images shows what happens at the various monitoring points in the processing chain. Note that, as each image is shown, the relevant monitoring point is emphasized in the block diagram above it.
These images demonstrate that the Apertif beamformer is getting in shape to be tested in full detail. All blocks are lined up, data is flowing as expected, and the Python scripts to control the boards are working. We look forward to an exciting period of further lab-tests, integrated with the other analog boards. This should then lead to the ultimate trials at the WRST telescope, with real celestial data!