I realized that in the calculation of the total DAC noise, I overstimated it by a factor 2 (klog 13589).

In the previus calculation the DAC noise contribution for each TM was estimated as following:

1) DAC_noise_TM=TF_TM_L2Darm*c

-In this espression I didn't take into account that the DAC noise pushes 4 coils incoerently. If we consider this, the corrected formula should be:

2) DAC_noise_TM=1/2* TF_TM_L2Darm*c

- I didn't take into account the effect of the DW filters engaged at ITMs.

By taking into account the DW filter attenuation (about a factor 10 at 10 Hz), eq2 can be written as:

3) DAC_noise_TM_dw=1/(2*10)* TF_TM_L2Darm*c

Considering this, today I estimated the DAC noise at TM stage by using eq 2 for ETMs and eq 3 for ITMs.

The attached plots show the results of this calculation:

-Pic1 shows the DAC noise projection measured at IX (DW filter), EY (w/o DW filter) and the total DAC noise contribution (sqrt (IX^2+IY^2+EY^2+EX^2))

According with this plot seems that around 100 Hz we are limited by the ETMs DAC noise.

-Pic2 shows the DAC noise projection when the DW filters are engaged to IX and EY, the total DAC noise contribution when the DW filter are used on all TMs and the total DAC when the DW filter are turned on only at ITMs.

According with this plot the total DAC noise will be reduced by a factor 10, by turning on the DW filters at ETMs.

*Note

I am assuming that the IY and EX DAC noise contributions should be equal to IX and EY ones respectively because the IY TF from TM_L to DARM is equal to IX ones and  the EX TF from TM_L to DARM is equal to EY ones. (see Pic1 in klog 13589)