In case you don't see the pictures attached to this report please click here: 10120.

In the commented entry it was reported that the DC control noise for the GAS filters was too high. I rolled-off the filters using a high-order Butterworth filters (12th order at 4 Hz) and achived an amount of noise below the requirement. See pictures. However, more analysis is necessary:

• Stability should be checked.
• The order of the filter seems too high, people have suggested me to use Chebyshev or Elliptical low pass filters instead.
• The measured sensitivity of displacement sensors are also shown.