[Miyakawa, Ushiba, Yoshioka]
We measured the transfer function from the compensation filter (outside the PSL) to ISS Servo (inside the PSL).
The compensation filter and Servo are connected by a 30-m cable. And Fig.1 shows the measurement result.
We calculated the transfer function of ISS Servo in the PSL room by removing the transfer function of compensation filter and phase delay of two 30-m cables from this measurement.
And I compared transfer functions of ISS Servo inside and outside the PSL room (see Fig.2). Then I found that Servo has a phase delay in the PSL room.
Finally, we took Servo out from the PSL room.
We will set the Integrator to a lower frequency and install it again, because there is no phase margin and the integrator cannot be turned on.
