We analyzed the ETMX coil driver TF measurements taken in June (klog 9288) for the high-power coil-driver chassis S1706257.

In this report we show:

• the fitted ZPK parameters of the high-power coil driver transfer function (with low-pass filters turned off),
• and the parameters of the low-pass filters (LPFs).

Although we found reasonable parameters of the coil-driver response, LPF fits give the gain of 1.03 for each of the LPF stage (expected gains are 1.0). It is possible that this fitting result is biased due to the fact that we measured only down to 1 Hz. Next time we should try measuring down to 0.1 Hz to verify if this 3% difference is real or just a fitting artifact. Zeros and poles of the LPFs are close to the expected theoretical values of z: 10.5 Hz and p: 1.0 Hz.

Average ZPK for the four TM coil drivers are (the gain is scaled by a factor of 3 at the monitor port of the satellite box):

    k: 0.377357 +/- 0.000049

    z: [18616.63 +/- 340.47]
    p: [13359.35 +/- 121.22, 29330.36 +/- 306.81]

Average ZPKs for the three LPFs (each coil driver has three LPF stages):

LPF1:
    k: 1.029 +/- 0.001

    z: [10.53 +/- 0.008]
    p: [ 0.98 +/- 0.001]
LPF2:
    k: 1.029 +/- 0.001

    z: [10.52 +/- 0.007]
    p: [ 0.98 +/- 0.001]
LPF3:
    k: 1.029 +/- 0.002

    z: [10.52 +/- 0.014]
    p: [ 0.98 +/- 0.002]

In the analysis of these measurements we removed the measured responses of the SE-to-Diff and Diff-to-SE adapters, by initially measuring TFs of all four channels of these interface boards before connecting them to the coil driver chassis. Measurement files, scripts and plots will be uploaded to the CAL group's git repository (NCU and GitLab.com).