|Description:|| The Tied Array Distributor unit (TADU) has been in the works for many years and, finally, results indicate that it will be fully commissioned soon. It will deliver flexible tied array data from the combined 14 WSRT telescopes to the two applications that require such data: the PuMa2 pulsar backend and the VLBI recorder.|
The project has had to deal with many changes in specifications and technology approaches over the years. The final system is a very flexible, all digital system, that produces VLBI Mk5b compatible data.
Recently the VLBI application was tested in a three station VLBI experiment: the Torun telescope in Poland (Tr) was used to correlate with the TADU output (Wb, 13 telescopes) and a single WSRT telescope (Wa). The image shows the successful detection of fringes on the baselines Tr-Wa and Tr-Wb at 4 MHz bandwidth in this example. The top two panels show correlated amplitude and the bottom two phase, both over frequency, for four subbands plotted next to each other. Clearly, TADU produces very nice bandpasses and phases. The colours denote cross correlated polarization channels: red is LL, blue is RR and the other ones RL and LR.
The ROD wishes to thank the R&D team, headed by Arie Doorduin, and Bob Campbell and the Jive team for doing the correlations and data analysis. Expect cake in the canteen soon to celebrate this milestone!