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Entry  Wed Jan 29 14:49:48 2020, anchal, DailyProgress, BEAT, Beanote Spectrum vs FSS Gain Values Beatnote_vs_FSSGain.pdf
    Reply  Wed Jan 29 15:58:26 2020, anchal, DailyProgress, BEAT, Beanote Spectrum vs FSS Gain Values Beatnote_vs_FSSGain.pdf
       Reply  Fri Feb 7 09:57:32 2020, anchal, DailyProgress, BEAT, Spanned gain parameter space in NFSS and checked beatnote NFSS_Spanned_Beatnote_Variation.pdf
          Reply  Fri Feb 7 18:12:03 2020, anchal, DailyProgress, BEAT, Spanned gain parameter space in SFSS and checked beatnote SFSS_Spanned_Beatnote_Variation.pdf
             Reply  Mon Feb 10 11:07:33 2020, anchal, DailyProgress, BEAT, Spanned gain parameter space in PMCs and checked beatnote PMC_Spanned_Beatnote_Variation.pdf
                Reply  Thu Feb 13 15:27:18 2020, anchal, DailyProgress, BEAT, Further iterated back and forth to optimized FSS Gains. FSS_Gain_Span.pdf
Message ID: 2525     Entry time: Fri Feb 7 18:12:03 2020     In reply to: 2524     Reply to this: 2526
Author: anchal 
Type: DailyProgress 
Category: BEAT 
Subject: Spanned gain parameter space in SFSS and checked beatnote 

I took beatnote measurements and spanned gain values (COM and FAST) on South side to see the variation in beatnote with them.


Method

  • I used BNspec.py with default settings (10 kHz bandwidth at 15.625 kSa/s for 60s) while spanning the parameter space of NFSS gains.
  • Every time the gain values are changed, a gainCycle.py is done and script waited for 10s before attempting beatnote measurement to let loops settle down.
  • The beatnote frequency was robustly within 2 kHz of 27.34 MHz during this whole measurement.
  • Overall experiment was run by spanParamSpace.py script.

Inference

  • I calculated the integrated total beatnote frequency noise in the frequency range 200 Hz to 1 kHz where the total noise is expected to be dominated by coating Brownian noise.
  • Unstable regions in the parameter space are clearly visible.
  • But as to the stable region, once the loop gets onto that, the noise does not change much, similar to North side.
  • So here as well, it seems like the beatnote noise is largely independent of the gain settings.
  • I'm unsure if I should look at this and the last measured data sets differently. Maybe I'm missing something.

Data

 

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SFSS_Spanned_Beatnote_Variation.pdf
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