Since we want to know if the AA diagonalized signals are dominated by PR/BS motion. So we want to use a transfer function to calibrate PR/BS motion into AA diagonalized signals. There is excitation sent to PR/BS p/y when the measurement is done. The excitation is as following:

The measurement of transfer functions are attached as four figures. It is shown in them that there were some coherence between 10~20Hz. We could multiplify this spectrum with PR and BS oplev signal and compare it with the diagonalized AA signal.