Using alogs 47217 and 45734 as a guide, we measured/calculated a new OMC-DCPD_MATRIX.

Note: this might have to be redone if we update the anti-TIA filtes for the DCPDs, see alog 76228.

We measured the coherent signal amplitude ratio g = PD_A/PD_B above 30Hz (i.e. above the TIA transfer function imbalance), so the matrix is optimized where we actually care.

g=1.0471

We measure the shot noise signal amplitude ratio h = PD_A/PD_B above 400Hz to avoid thermal noise and correlations from the feedback.

h=1.0247

This produced the new output matrix (see secript)

0.99861 1.00139
0.97725 -1.02328

For reference, old matrix:

0.99963 1.00040
0.98198 -1.0184

The new matrix was loaded, but not yet tested - the IFO lost lock due to 43kts wind gust.