I injected a line at 8.5 Hz in both CHARD yaw (amplitude 1.0) and INP1 yaw (amplitude 3e6) and measured the response of the REFL WFS (in units of WFS / loop output)
| CHARD YAW | INP1 YAW | |
|---|---|---|
| REFL_A_RF9_I | -0.00265 | 0.227 |
| REFL_B_RF9_I | -0.00296 | 0.113 |
| REFL_A_RF45_I | -0.00240 | 0.351 |
| REFL_B_RF45_I | -0.00272 | 0.237 |
The RF9 signals have a slightly better SNR than the RF45 signals, so I inverted the 2x2 RF9 matrix (and rescaled so that the response should be the same as the input matrix in guardian)
| REFL_A_RF9 | REFL_B_RF9 | |
|---|---|---|
| CHARD | -1.50 | 3.68 |
| INP1 | 1.00 | -0.88 |
For comparison, now we are using the following input matrix:
| REFL_A_RF9 | REFL_B_RF9 | REFL_B_RF45 | |
| CHARD | 1.00 | 0.20 | 1.30 |
| INP1 | 1.00 | -0.40 | -0.20 |
This matrix has the same response as the new ones for the diagonal CHARD > CHARD and INP1 > INP1 elements, but the off diagonal element from INP1 to CHARD is much larger.
Finally, to have a complete picture we should measure the PRC1 and PRC2 response in the REFL WFS.