Yuhang and Marc

We would like to have 'tilt driving' coupling to 'shift driving' as small as possible. To achieve this, we worked on finding optimal driving matrix for H1 and H3 for pitch today. 

At the beginning, the driving matrix for pitch is: H1 0.794, H3 1. This was optimized in the past. However, we would like to optimize it again since we glued new magnets at the beginning of this year.

To check how much coupling we have, we sent 5Hz 5000 amplitude for INPUT_PIT_ex2. We checked coherence between GR_CORR and excitation, no coherence was found.

Then we checked when driving matrix is: H1 1, H3 1. We found no coherence even in this case. We checked the connection, we found later on that actually GR_CORR is not connected.

After putting back good connection of GR_Corr, we take data when H1 and H3 are both 1. We saved as reference as blue (REF0 and REF1).

H1 0.794, GR_corr 17.964 (REF2, REF3)

H1 1,         GR_corr 30.475

H1 0.6,      GR_corr 13.38

H1 0.5,      GR_corr 15.82

H1 0.55,    GR_corr 13.82

H1 0.65,    GR_corr 13.09

H1 0.65, H2 0.02,  GR_corr 12.63

H1 0.65, H2 0.05,  GR_corr 13.61

H1 0.65, H2 0.01,  GR_corr 12.30

H1 0.65, H2 -0.01,  GR_corr 12.82

When we drive H1, we get GR_corr 87.08

When we drive H3, we get GR_corr 63.24

We found a ratio of 0.73. Then we did H1 0.73, we get GR_corr 10.71

Attached figure shows a comparison of GR_corr when H1 is 1 or 0.73.

We still have coupling as we see the number in GR_corr 10.71. We still would like to understand it better what is causing this number. One thing we will check is the coupling factor when different amplitude signal is sent to H1 and H3. We will also test this coupling number by sending excitation at a different frequency.