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Message ID: 2534     Entry time: Thu Feb 13 18:06:00 2020
Author: anchal 
Type: DailyProgress 
Category: NoiseBudget 
Subject: Adding dark noise measurement of beatnote detector SN101 

I measured dark noise of the beatnote detector reaching moku and its effect on measured beatnote frequency noise.


  • I used Andrew's low noise preamplifier to measure this noise.
  • I first took the transfer function through the preamplifier so that everything later can be referenced back to its input.
  • I measured measurement setup noise by shorting the input to the pre-amplifier.
  • Then I measured dark noise after the 20 dB coupler (the cable that I connect to moku) when the detector was completely blocked with a beam dump.
  • The noise was converted to precieved beatntoe frequency noise by using peak to peak voltage of beatnote signal. (Noise*freq*2*pi/Vsigpkpk)
  • The noise came a little less than Tara's measurement. I'm updating my noise budget model with this now.


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