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Entry  Thu Jul 16 18:28:53 2015, Arjun, Misc, PD noise, PD noise update Sim_vs_Obs_OLG.figSim_vs_Obs_OLG.pdfNoise_plots.figNoise_plots.pdf
    Reply  Fri Jul 17 18:12:36 2015, rana, Misc, PD noise, PD noise update 
       Reply  Sat Jul 18 22:24:08 2015, Arjun, Misc, PD noise, PD noise update 
Message ID: 1980     Entry time: Thu Jul 16 18:28:53 2015     Reply to this: 1983
Author: Arjun 
Type: Misc 
Category: PD noise 
Subject: PD noise update 

Today, I implemented the intensity servo and characterised it using the voltage injection method to calculate its loop gain. I also compared it with the simulations for the same that I performed on LISO. I have attached the figures below. I also completed the circuit I made to measure the differential signal of the PDs(its just a voltage regulator setup with a AD620 with a gain of 100), but I could not characterize or take measurements using that. I will do that tomorrow. 

1) RIN with and without feedback( both in-loop and out-of loop). The gain for this loop was set at 200, this was to compensate the -16.5dB loss in the remaining setup(AOM, RF function generator etc).

2) Open loop gain Transfer function- simulated and measured.

I am still stuck on how to measure the difference in the reponse of the two transimpedence amplifiers on the photodiode readout board, I have a few ideas, I am assessing their validity.

Attachment 1: Sim_vs_Obs_OLG.fig  25 kB
Attachment 2: Sim_vs_Obs_OLG.pdf  8 kB  | Hide | Hide all
Attachment 3: Noise_plots.fig  107 kB
Attachment 4: Noise_plots.pdf  25 kB  | Hide | Hide all
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