Unity Gain Frequency Monitor (GainMon)

--Aaron Rogan, Mike Landry, Sukanta Bose

What is GainMon?

The GainMon will act as a real time continuous monitoring tool for the unity gain frequency for the DARM control loop. Subsequently, the functionality of GainMon will be extended to output the UGFs for the PRC and MICH loops as well.

What is needed?

• A method of determining the unity gain frequency for the DARM control loop.

• A real time monitor that outputs the gain frequency continuously

What is already in place?

• Matlab code in the package NoiseBudget already is set up to calculate the unity gain frequency

• The current getUGF.m code reads in both IFO and noise parameters which are illustrated above by par and noise_par respectively. The last piece of information that the code needs to calculate the ugf is the current model of the DARM control loop. This is hard coded in the matlab file.

• SenseMonitor is a monitor that will automatically create and populate tables continuously with effective distances computed for a given IFO. It has been coded to have access to most of the same information that is needed to calculate the ugf.

• The above flow chart lists the minimal requirements for running SenseMonitor. It requires the operating state condition (OSC) of the given IFO and some calibration information. It then outputs in real time the effective distance that the given IFO is currently operating at.

What has to be done?

Combine these two codes into one. This entails turning the matlab code into a standalone compiled function that is capable of running outside the matlab environment. The changes should be minimal and mostly involve just incorporating the getUGF code into a cloned version of SenseMonitor; this is what we call GainMon. The changes to getUGF.m will be adding the current model as one of the calling parameters for getUGF.m instead of reading it in inside the function itself. This current model will then need to be passed to the GainMon function call. Other than incorporating the getUGF function into the new monitor, the remaining changes should be minimal and basically just consist of ensuring the new monitor is outputting the ugf instead of effective distance.