[Pinkesh, Sam]
In setting up a Digital based control of the hanging OMC, we naively connect the Anti-Imaging filter output to an Anti-Aliasing input. This led to no end of hell. For one thing, we found the 10 kHz 3rd order butterworth at 10 kHz, where it should be based on the install hardware. One wonders in passing whether we want a 10 kHz butter instead of a 15 kHz something else, but I leave that for a later discussion. Much more bothersome is a linear phase shift between output and input that looks like ~180 microseconds. It screams "What the hell am I!?" and none of us could scream back at it with an answer. I believe this will require the Wilson House Ghost Busters to fully remedy on the morrow. |