[Tamaki, Ushiba]

Since AEL groups provided AA filters, which has higher cut-off than the nominal one at ch 20 - ch 27, we installed it for ADC0 of OMC0 rack.
Then, we performed dark offset measurement for AS PDs and QPDs, which is connected to ADC0.
After that, IFO can be locked without any problems and no significant difference can be seen in the sensitivity.

S numbers of the circuit will be posted by Tamaki-kun, probably.