J. Kissel

I've measured high precision transfer functions of every relevant channel of H1 SUS ETMX's AI chassis today from 10 [Hz] to 100 [kHz]. This was mostly a dress rehearsal because EY wasn't available, but eventually we may be using both QUADs to actuate DARM so we'll need these for calibration accuracy, and this felt like a good time to measure, since the rest of the world was down for upgrades. I'll measure EY tomorrow.

The messages: 
- all channels are functioning fantastically, 
- there is a DC gain of 0.9897 +/- 0.0001 [V/V] on all AI chassis' channels I've measured, 
- the notch frequency is 65883 +/- 374 [Hz], 
- and by 2 [kHz] there's already a 2% drop in gain from that (though we're not surprised by this).
We will use these measurements (well, ETMY's are more important currently, but...) to inform the calibration model.

Attached are several things:
2015-05-19_H1SUSETMX_AIChassis.pdf
Plots of the results, showing the full frequency response from 10 to 1e5 [Hz] and a zoom in on the gravitational wave band.
The last plot shows the data analysis performed to transform the raw data into the final answer -- I measured the full signal chain both with the device under test (DUT) and by-passing it as a reference, and then taking the ratio to find just the DUT's response.

2015-05-19_AIChassis_Measurement.pdf
Diagrams showing the measurement setup. Thanks to the good Dr. O'Rielly for the verbal list of tips/tricks/"gotchas."

2015-05-19_H1SUSETMX_AIChassis_Meast_Pics.pdf
Pictures of the setup to aide the diagram.

Details:
All raw measurements, and results can be found committed to the CalSVN repo here:
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER7/H1/Measurements/ElectronicsMeasurements/

The analysis script which takes out the reference transfer function and makes plots:
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER7/H1/Measurements/ElectronicsMeasurements/process_H1SUSETMX_AI_Measurements_20150519.m

Of particular interest for the future is the SR785 measurement readout scheme, in which I used a GPIB box configured against a portable wireless router that can access the CDS network (thanks to Elli and Evan for helping me with this). As such, I could run the GPIB measurements from a nearby work-station, and all data retrieval is automatic without the need for clumsy floppy-disk or USB drives. Note that this process uses the latest checkout of the github repo for this stuff maintained by Eric Quintero at the 40m Lab,
https://github.com/e-q/netgpibdata/
which has now been checked out in an "official" location here:
/ligo/svncommon/NetGPIBDataGIT/netgpibdata/
where the key function (for a transfer function measurement) is
/ligo/svncommon/NetGPIBDataGIT/netgpibdata/SRmeasure
and parameter file template
/ligo/svncommon/NetGPIBDataGIT/netgpibdata/SPSR785template.yml
So to take such a measurement, you
- Connect the GPIB to the SR785 and to the wifi router
- Setup of the SR785 "OUTPUT" button to have Destination as "GPIB," GPIB Control as "SR785," and GPIB Address as "[some number]," where "[some number]" is defined in the first few lines of parameter file. 
For this measurement setup, I tried to make the measurement parameters as identical to what I found on the LLO CDS machines in
/data/brian/gpib/configuration.py
where Brian told me to hunt. My configuration file now lives in the CalSVN repo in the same place as everything else for these measurements,
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER7/H1/Measurements/ElectronicsMeasurements/TFSR785_AIChassis_Config.yml
thus, to run a given measurement, I can run the following command (assuming I'm in the CalSVN ElectronicsMeasurements directory),
]$ /ligo/svncommon/NetGPIBDataGIT/netgpibdata/SRmeasure ./TFSR785_AIChassis_Config.yml
and ~10 minutes later I get a happy little .txt file export of the measurement from the SR785 in that directory. Sweet!