We performed the tapping test for OMC chamber including the geophone.
Red : Geophone
K1:PEM-ACC_OMC_VACTABLE_OMC_Y_OUT (dush : reference)
Blue : Accelerometer on the OMC chamber (Fig.1.)
K1:PEM-PORTABLE_OMC_BOOTH_OMMT_BNC1_OUT (dush : reference)
As you can see, even there are some differences, noise level became larger when tapping the OMC chamber.
And the noise level larger when we tapped the side of chamber than top of chamber.
We performed the shaker injection (swept, band-limited white) for the berrows leg (-Y side).
Fig.1 is the spectrogram (ASD) and Fig.2 is relative to the reference.
The response looks linear below 160 Hz.
The high-frequency response is up-converted. (due to the table? or the geophone?)
I checked the spectrum, coherence, and transfer function for the 60-200Hz shaker injection data.
Note that the direction is different.
