06:19 - 06:49 swept sine acoustic inejction at Xfront
Low frequency 50 Hz
High frequency 300 Hz
Rate 1800 sec
Gain 300 count
Excitation channel K1:PEM-EXCITATION_EX0_RACK_2_EXC
Result : Fig1.
One large glitch seemed the IPC glitch.
There are multi frequency conversion around 116 Hz.
06:53 - 07:23 swept sine acoustic inejction at Yfront
Low frequency 50 Hz
High frequency 300 Hz
Rate 1800 sec
Gain 300 count
Excitation channel K1:PEM-EXCITATION_EX0_RACK_2_EXC
Result : Fig2.
Two large glitch seemed the IPC glitch.
Several glitch happened in IXC microphone as shown in Fig.3.
08:00 - 08:05 swept sine acoustic inejction at Xfront
Low frequency 110 Hz
High frequency 130 Hz
Rate 300 sec
Gain 300 count
Excitation channel K1:PEM-EXCITATION_SR3_RACK_2_EXC
08:06 - 08:11 swept sine acoustic inejction at Yfront
Low frequency 110 Hz
High frequency 130 Hz
Rate 300 sec
Gain 300 count
Excitation channel K1:PEM-EXCITATION_SR3_RACK_4_EXC
Three transient behaviors in the first post, which Yokozawa-san mentioned, were due to the IPC glitch.
The transient behaviors in the second post were unknown.. The cause seems to be different from the IPC glitch.
By the way, since 2024/12/12 13:22 JST, the number of IPC glitch started increasing. I attach the list. The timing looks at random, not concentrating at specific time.
125 - 130 Hz several linear response
~125 Hz sideband like signal (118 Hz and 135 Hz)
~ 117 Hz wide frequency response around 117 Hz (sometimes X like shape?)
https://gwdet.icrr.u-tokyo.ac.jp/~controls/hveto/day/20241213/scans/1418085323.46875/
The round winner in Hveto is K1:VIS-ITMY_TM_WIT_Y_DQ, but the glitch shape that appears around 100 Hz in DARM signal is similar to the glitch that appears in the REFL RFQPD.
Glitches in the REFL RFQPD signal may shake the Type-A suspension via ASC CHARD control signal. This may be the reason why Hveto determined that it was coincidence with ITMY.