For OMC beacon ASC, I checked several things.

1. DC centering loop:

I turned on PZT offsets for OMC bacon QPD centering loops and roughly centered the beam by picomotors.
Then, I trned on the loop manually (turn off FM8 (null)) and confirmed that it works well.

2. Phasing of RF17 demodulation:

I measured the spectrum of K1:ASC-OMC_REFL_QPDA{1,2}_RF17_{I,Q}{1,2,3,4}_ERR signals and see the ratio of the peak height (fig1: QPDA1 and fig2:QPDA2).
Then, I rotated demodulation phases to minimize Q signals.
Figure 3 and 4 shows the medm  screens after implementing new demodulation phases (fig3:QPDA1 and fig4:QPDA2).

3.Phasing of 23.4991 kHz demodulation:

I also check the phasing of beacon signal demodulation.
Figure 5 shows the phase from oscillator to beacon signals in RF17_I of each segment.
According to the measurement results, I implemented demodulation phase to each segment as shown in fig3 and 4.
Figure 6 and 7 show the signals after demodulation with 10Hz low-pass filter of QPDA1 and QPDA2, respectively.
Some jumps in the signals are due to the change of demodulation phase.
All Q signals become close to 0, so the new demodulation phases see to be fine

Note:

Measured data are stored at /users/Commissioning/data/ASC/2024/1006/.