Aritomi and Yuhang

Since the unity gain frequency of CC2 was only ~400Hz because of some resonance. We decide to put some more damping material. 

So we put some double layers bent rubber(as shown in the attached photo1) in the position where there may be some spring resonance(as shown in attached photos 2 and 3).

Then we measured OLTF, which is shown in the attached photo 4. And it is shown that the unity gain frequency is around 2kHz now. We also tried to increase the gain, we measured the resonance frequency when there is oscillation. As shown in the attached photo5, the oscillation is at ~23kHz. 

We also measured OMTF. By comparing the measurement we did before putting this new damping rubber, we found the peak around 1 and 2kHz disappeared(as shown in the attached figure 6).