[Patrick, Jan]
We traced the 12kHz oscillation that we were struggling with down to the problem that there is no impedance in the output of the AI filters. This caused a oscillation at high frequencies which apparently coupled into the PZT ramp signal (ramp is generated digitally). We build an adapter with 100 Ohm resistors between input and output of the 24 channels and this solved the problem. Since this problem is also present in all other channels (PMC, ISS, FSS) we will look for some board redesign or adapters for those channels too (currently in discussion with Peter King)