I wrote a script to measure the ISS RIN. The script uses the "labca" interface (described in an earlier entry) to read and twiddle EPICS settings and mDV to get DAQ data. The script measures open loop RIN, closed loop RIN at each of several gain slider settings, and dark noise. The dark noise is obtained by misaligning (unlocking) the PMC. The script also compares the whitened and unwhitened spectra for an open loop measurement and performs a fit of a simple pole to find the dewhitening filter.
This is all very exciting, but I don't quite believe the results, since the closed loop RIN seems to bottom out at 2e-7/rtHz regardless of the gain slider setting.
Sample output attached. The script may be found at scripts/PSL/ISS/rin.m. |