camilla - 18:13 Tuesday 17 December 2019 (12187)
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Comment to PSL shaker injection (12151)
I made the projection of one of the PSL accelerometers (PERI_PSL2_X) on darm, during the injection with the shaker at 80 Hz.
The gps start is 1260408911, the duration 100s. As a reference I took 100s starting from gps 1260409811.
The 1st plot shows the spectra of microphone, accelerometer and darm during the injection and their backgrounds. There are some peaks appearing in darm (at 35,41,86 Hz) which are not due to the injection, so they shouldn't be taken into account in the projection.
Plot 2 shows the projection and the upper limit of the accelerometer signal.
The conclusion is that the only points we can trust are the ones close to 80 Hz, and that at this frequency the beam jitter noise is a factor 100 below the sensitivity. Of course this kind of measurement should be done again to look at other frequencies.
Thanks to Washimi, Tanaka and Irene for their advices.
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