After the AA loop could be closed with high UGF, the locking noise was not checked again. So I did this check today.

The PR and BS local control was closed all the time. Then I measured locking noise when AA loop is closed or open. The result is shown in the attached figure.

The locking noise level is much higher than the one reported in elog2231, which has lower AA UGF.

If we compare the shape of the locking noise spectrum, it is very similar with the diagonalized AA_INPUT_PIT.