E. Goetz, J. Kissel

We're getting serious about measuring the thermalization during the engineering run to better understand how the systematic error in calibration evolve during the first ~6+ hours after power up to 75W, so I've taken the time this morning to settle on number of lines, their frequencies, and their amplitudes before I push them into a guardian node using awg. In short -- two changes from when I last resurrected the lines,
   (1) I'm adding two more line pairs, and
   (2) I'm driving PCALY instead of PCALX because after the reduction of the TDCF line amplitudes there's now much more available range on PCALY than PCALX.
   (3) I'm choosing line frequencies based on being bin-centered in a 40 sec FFT (the same as we did in O3)


H1:CAL-PCALY_PCALOSC4_OSC_FREQ      8.925     3000
H1:CAL-PCALY_PCALOSC5_OSC_FREQ     11.575     1000
H1:CAL-PCALY_PCALOSC6_OSC_FREQ     15.275     120
H1:CAL-PCALY_PCALOSC7_OSC_FREQ     24.500     80

H1:LSC-DARM1_EXC                    8.825      5.0e-9
                                   11.475      1.2e-9
                                   15.175      3.0e-10
                                   24.400      1.0e-10

The PCAL and DARM line amplitudes are tuned to the "coherence be consistently above 0.99" using DTT's closest thing to a 40 second FTT, which one might think means entering 0.025 in the BW (and I've done so), but really that yields at 32 sec FFT. Nothing fancy here, and I didn't spend more than 20 minutes on doing this, so nothing's perfect. I've not yet considered the impact on BNS range. We should probably have subtraction teams add this to their list though.

Note, these tests today were driven by individual oscillators for the PCAL system. When things are coded up into guardian using AWG I'll need a standard filter module's excitation channel (like the DARM_EXC channel). As such I'm going to chose H1:CAL-PCALY_DARM_EXC (the old filter bank that was creating for testing whether we had the range to control DARM by driving the QUAD with PCAL instead of its ESD at the lowest stage). As with the oscillators, this channel is not independently stored in the frames, but everything is summed into H1:CAL-PCALY_EXC_SUM_DQ before heading out to the DAC. In reality, when the analysis is performed, we use the RX_PD readback channels, which are nicely already calibrated into DARM displacement [meters].