Date: 2024/8/6

With Yokozawa

Summary

Filters in K1 ITMY MN DAMP for L and T were updated.
First, we copied FM2(ELP30) and FM3(ELP9) from the ETMX filter banks to the ITMY filter banks.
Then, we adjusted the ELP9 filters and notch filters to have better suppression ratio for the peaks and low gain peaking (should be < 6dB)
Measured OLTFs before/after the adjustment were attached.
xml files are in "/users/Commissioning/data/VIS/ITMY/2024/0806/"

Details

• Adjustment for DAMP L with ELP9
  • Requested PAY_FLOAT for the ITMY suspension
  • Closed NBDAMP L1-3
  • Excitation preparation
    • Excitation filter: `("BandPass",4,0.01,10)` -> `butter("LowPass",4,10)zpk([2],[0.1],1,"n")`
    • Excitation Amplitude: 80
  • Fiter adjustment
    • notch: `notch(5.28,10,60)` -> `notch(5.18,10,60)`
  • Result
    • Peak reduction at 0.64Hz: -8.0dB
    • Peak reduction at 1.48Hz: -17dB
    • Peak at 5.09Hz: +2.5dB
    • Gain peaking at 1.5Hz: +4.2dB
• Adjustment for DAMP L with ELP (this was not needed.)
  • Copy the ELP30 of ETMX to the ELP of ITMY MN DAMP L
  • Excitation filter: `butter("LowPass",4,10)zpk([2],[0.1],1,"n")`
  • Excitation Amplitude: 50 -> 40 -> 20
  • NB filters were ON during this work...
  • ELP filter: "ELP_old" -> `elip("LowPass",4,1,100,30)gain(6,"dB")` -> `elip("LowPass",4,1,100,30)gain(9,"dB")`
  • Result
    • Peak reduction at 0.64Hz: -19dB
    • Peak reduction at 1.48Hz: -29dB
    • Peak at 5.09Hz: +dB
    • Peak at 1.7Hz: +2.6dB
• Adjustment for DAMP T with ELP9
  • Turn ON NBDAMP T1-3
  • Excitation Filter: `butter("BandPass",4,0.1,10)` -> `butter("LowPass",4,10)zpk([2],[0.1],1,"n")` -> `butter("LowPass",4,10)zpk([2],[0.1],1,"n")zpk([10],[1],1,"n")`
  • Excitation Amplitude: 10 -> 50 -> 400 -> 350
  • Filter adjustment
    • Removed LP which was FM2
    • Add ELP30: `ellip("LowPass",4,1,100,30)gain(1.12202)`
    • Add LOCK+ELP9: `ellip("LowPass",4,1,100,9)gain(1.12202)gain(-10,"dB")` -> `ellip("LowPass",4,1,100,9)gain(1.12202)gain(-9,"dB")` -> `ellip("LowPass",4,1,100,9)gain(1.12202)gain(-5,"dB")` -> `ellip("LowPass",4,1,100,9)gain(1.12202)gain(-2,"dB")` -> `ellip("LowPass",4,1,100,9)gain(1.12202)gain(1,"dB")` -> `ellip("LowPass",4,1,100,9)gain(1.12202)gain(3,"dB")` -> `ellip("LowPass",4,1,100,9)gain(1.12202)gain(5,"dB")`
    • Pnotch: add `notch(2.50,20,30)` -> add `notch(5.15,20,30)` -> change to `notch(5.15,10,30)`
    • The final filters:
      • FM1 = DAMPzpk: `zpk([0],[25],1,"n")gain(60,"dB")gain(-5.95,"dB")`
      • FM3 = LOCK+ELP9: `ellip("LowPass",4,1,100,9)gain(1.12202)gain(5,"dB")`
      • FM8 = Pnotch: `notch(9.32,50,60)notch(32.9,50,60)notch(44.11,50,60)notch(7.4,50,60)notch(2.50,20,30)notch(5.15,10,30)`
• The filter ELP30 was just copied from ETMX.