End-to-end Testing of the ARTS Firmware

© J Hargreaves, P Donker

Signals collected by the WSRT Apertif phased array feed may have finished their journey across the Universe, but they are about to begin a far more perilous voyage through the ARTS/Apertif firmware.

Numerous hazardous re-orderings, transposes, re-quantizations, beamformings and channelizations await.

In order to ensure that all the signals are delivered safely into the expert hands of astronomers, the Desp firmware team has begun developing a suite of end-to-end tests. Each element in the array

can be replaced by a sine-wave generator, programmable in amplitude and frequency. For ARTS Science Case 4, we can connect each element to its own 'single-element' compound beam. Then we

sweep the sinusoid through the entire frequency band, switch to the next element and repeat until the signal has been applied to all forty compound beams. Some early results are shown here.

It is important that the signal shows up only on the Arts cluster node allocated to that compound beam, and nowhere else. We are developing scripts to check this automatically. Note

the expected gaps in the 'limited-bandwidth' compound beam, cb3: a built-in test of the test!

Further tests will include fine-grained frequency sweeps to measure the channelizer bin characteristics, and amplitude sweeps to check the quantization and saturation levels.