As requested by Nakano-kun, a plot showing the coherence btw PSL table ACC and REFCAV err is attached here. There are high coherence at 75 Hz and a little coherence at ~40Hz.

For your information, K1:PSL-PMC_REFL_DC_OUT_DQ channel was connected to the accelerometer placed on the PSL table temporarily, from UTC 9/15 6:10:00 for about two hours (thanks to Nogai-kun!). If you would like to investigate the coherence more, please use that channel and the timing.