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NAC source -- data from UT2014-04-25-00:00

PHASECAM – April 25 th status. NAC source -- data from UT2014-04-25-00:00. OPD-tip/tilt correlation. Tip -tilt. OPD. OPD-tip/tilt correlation. Tip-tilt not symmetric?. CG and phase loop blending. CG measurement too noisy at 1kHz: .

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NAC source -- data from UT2014-04-25-00:00

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  1. PHASECAM – April 25th status NAC source -- data from UT2014-04-25-00:00

  2. OPD-tip/tilt correlation Tip-tilt OPD

  3. OPD-tip/tilt correlation Tip-tilt not symmetric?

  4. CG and phase loop blending • CG measurement too noisy at 1kHz: -2.2 mm White fringe + 2.2 mm

  5. CG and phase loop blending • Phase actually stays within one cycle:

  6. CG and phase loop blending • => Averaging CG over 20 frames so that the histograms don’t overlap; • Define minimum CG error for one fringe jump (depends on phase setpoint!). • Tested successfully with our vibration simulator: • Merging tests under progress. Tricky because phase setpoint and CG setpoint correlated. Approach: • Run continuous averaging of CG. If CG > CGmin, send 2 mm or CG error and wait for CG to be ok (at 50Hz). Unstable so far… • Blend the two by weighting the CG correction and phase correction. Cannot use the CG error as weight because it cannot be trusted at 1kHz.

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