|
Gday Lee
For the upper graph, the left axis is in "axis" arcsecs.
This was just a grab of unguided, PEC off data, to see what the raw tracking was like. The large ripple due to the belt teeth shows very clearly, superimposed on the much larger worm error.
The lower graph is an FFT analysis ( similar to what PEMPro would do )
The left axis is scaled such that the maximum fundamental detected in the data becomes 1.
In my case, the worm ( ie fundamental 1 ) is plotted as 1.0, as it has by far the larges amplitude.
The no 36 fundamental is showing up as approx 0.11, and that indicates the PE caused by the belts meshing is approx 11% the magnitude of the primary PE of the worm, and hence is noticeable.
Andrew
|