Graeme, Matt, Craig

Using our setup from yesterday (alog 76397), we injected into the common mode board and measured a CARM to DARM transfer function.
Matt will post plots, comparisons, and measurement times later.

I am posting the data now, it lives in /ligo/gitcommon/psl_measurements/data/carm_to_darm_tfs/.

Just to clarify what these measurements are, we injected a 600 mV broadband white noise injection from 51.2 kHz to 102.4 kHz frequency span into the common mode board excitation point.
We measured out at the REFL A 9 QMON at the PSL racks (which is actually REFL A 9 I used for frequency feedback) and out of the OMC DCPD whitening chassis A+ terminal, patched over to the PSL racks as described in alog 76397.

We saw a significant rise in the REFL A 9 QMON noise as we injected more (Matt's plots to come), but very little increase in the OMC DCPD noise.
We had around 5e-3 coherence between the two at best.
We took 10000 averages, so we believe that anything above 1e-4 is "well-resolved".

We did not have time to try injecting between 1 kHz and 51.2 kHz before we lost lock, or to try looking at OMC DCPD A / EXC
We were not injecting at the time of the lockloss.  
We left the SR785 out there but not plugged in to anything on the racks so we can relock peacefully.

EDIT:
We went back out, got some data betwen 1 kHz and 52 kHz, and then unplugged everything, including the SR785 and the HAM6 OMC DCPD A+ whitening chassis cable.  We didn't unplug the patch panel connection.