Nergis, Sheila, Haocun

As posted in alog 27820, the IMC transfer function has a high gain around 800kHz, and we thought that may be reduced by lowering the FSS loop gain, which was proved to be true.

We reduced the FSS loop gain for 6dB (the common gain from 20dB to 14dB;  the fast gain from 22dB to 16dB) , and the IMC loop gain dropped about 16dB from -4dB to -20dB at 800kHZ.

The measurements were taken from 10Hz to 5MHz. The green curve was measured before reducing the FSS gain, and the yellow one was measured after lowering the gain.

Currently, we left the FSS loop gain values to be the lower ones, which can be turned back up later if needed.