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Entry  Fri Nov 1 17:54:47 2019, anchal, DailyProgress, FSS, FSS Diagnostics - RFPD RF Ouput under inspection NFSS_RFPD_Output_Oscilloscope.pdfSFSS_RFPD_Output_Oscilloscope.pdfNFSS_RFPD_RF_OUT_COUPLED.pdfSFSS_RFPD_RF_OUT_COUPLED.pdf
    Reply  Tue Nov 5 18:37:59 2019, anchal, DailyProgress, FSS, FSS Diagnostics - TTFSS Testpoint Spectrum Data FSS_TP_Spectrum.pdf
       Reply  Sat Nov 9 19:28:36 2019, anchal, DailyProgress, FSS, FSS Diagnostics - Loop nonlinearity Test NFSS_NonLinearity_Test.pngSFSS_NonLinearity_Test.pngsignal-attachment-2019-11-09-195635.jpeg
          Reply  Mon Nov 11 20:42:49 2019, anchal, DailyProgress, FSS, FSS Diagnostics - Two Tone Test NFSS_RFPD_SN009_TF_11-11-2019_183131.pdfSFSS_RFPD_SN010_TF_11-11-2019_203310.pdfFSStwoToneTest.pdf
             Reply  Tue Nov 12 18:36:59 2019, anchal, DailyProgress, FSS, FSS Diagnostics - Two Tone Third Order Intermodulation Test FSStwoToneThirdOrderIM.pdf
                Reply  Thu Nov 14 12:19:32 2019, rana, DailyProgress, FSS, FSS Diagnostics - Two Tone Third Order Intermodulation Test 
                   Reply  Tue Nov 19 18:51:02 2019, anchal, DailyProgress, FSS, FSS Diagnostics - Second-order Distortion Calculation FSSDistortionCalc.pdfFSSDistortion.zip
                      Reply  Mon Dec 9 19:54:44 2019, anchal, DailyProgress, FSS, FSS Diagnostics - How much distortion affects the functioning of PDH? 
       Reply  Wed Nov 27 13:59:24 2019, anchal, DailyProgress, FSS, FSS Diagnostics - TTFSS TP1 TimeSeries NFSS_TP1_Oscilloscope.pdf
          Reply  Wed Nov 27 15:17:51 2019, anchal, DailyProgress, FSS, FSS Diagnostics - Quick HF OLTF of NFSS NFSS_OLTF_HF.pdf
             Reply  Wed Nov 27 16:31:20 2019, rana, DailyProgress, FSS, FSS Diagnostics - Quick HF OLTF of NFSS 
                Reply  Wed Dec 4 18:11:09 2019, anchal, DailyProgress, FSS, Free running laser frequency noise spectrum PMCErrorSignals.pdf
                   Reply  Thu Dec 5 18:25:11 2019, rana, DailyProgress, FSS, Free running laser frequency noise spectrum 
                   Reply  Tue Dec 17 18:29:58 2019, anchal, DailyProgress, FSS, Need for ISS? 
                      Reply  Wed Dec 18 18:40:32 2019, anchal, DailyProgress, FSS, Maybe the NPRO Laser isn't bad after all NorthLaserRINAnalysis.pdf
                         Reply  Wed Dec 18 22:03:17 2019, rana, DailyProgress, FSS, Maybe the NPRO Laser isn't bad after all 
                            Reply  Fri Dec 20 15:00:30 2019, anchal, DailyProgress, FSS, PZT, EOM to RIN TF Measurement NorthLaserPZTEOMtoRINTF.pdf
                               Reply  Fri Dec 20 18:08:44 2019, anchal, DailyProgress, FSS, PZT, EOM to RIN TF Measurement Through FSS NorthLaserPZTEOMtoRINTFThruFSS.pdf
                                  Reply  Tue Jan 7 17:59:20 2020, anchal, DailyProgress, FSS, NPMC TF NPMC_TF.pdf
       Reply  Thu Dec 12 19:15:55 2019, anchal, DailyProgress, FSS, FSS Diagnostics - Beatnote Spectrum wrt Laser Power and Modulation Index BeatnoteSpectrumwrtPowerandModindex.pdf
       Reply  Tue Dec 17 16:55:07 2019, anchal, DailyProgress, FSS, FSS Diagnostics - TTFSS North U7 Boost Stage Input-Output TimeSeries NFSS_UT_TS_Analysis.pdf
    Reply  Tue Nov 12 11:39:48 2019, anchal, DailyProgress, FSS, FSS Diagnostics - RFPD RF Ouput under inspection 
    Reply  Fri Dec 13 16:24:02 2019, anchal, DailyProgress, FSS, FSS Diagnostics - RFPD Circuit Latest Available Photos SN009.jpgSN010.jpgSN009.jpgSN010.jpg
    Reply  Fri Dec 13 17:44:05 2019, anchal, DailyProgress, FSS, FSS Diagnostics - RFPD RF Coupled Output Offset 
       Reply  Mon Jan 13 19:04:38 2020, anchal, DailyProgress, FSS, FSS Diagnostics - SN009 (North RFPD) Notch Improvement Attempt SN009.jpgSN009_D980454-00-C.pdfSN009_Notch_Improvement_Attempt.pdf
          Reply  Tue Jan 14 18:19:33 2020, anchal, DailyProgress, FSS, FSS Diagnostics - SN009 (North RFPD) Notch Improved! SN009.jpgSN009_D980454-00-C.pdfSN009_Notch_Improvement_Attempt.pdf
             Reply  Thu Jan 16 11:17:15 2020, anchal, DailyProgress, FSS, FSS Diagnostics - SN010 (South RFPD) Notch Improvement Attempt SN010.jpgSN010_D980454-00-C.pdfSN010_Notch_Improvement_Attempt.pdf
                Reply  Thu Jan 16 20:18:44 2020, anchal, DailyProgress, FSS, FSS Diagnostics - SN010 (South RFPD) Notch Improved SN010.jpgSN010_D980454-00-C.pdfSN010_Notch_Improved.pdf
                   Reply  Mon Jan 27 18:29:19 2020, anchal, DailyProgress, FSS, FSS Diagnostics - RFPD RF Out Spectrum FSS_RFPD_RFOut_Spectrum.pdf
Message ID: 2476     Entry time: Sat Nov 9 19:28:36 2019     In reply to: 2474     Reply to this: 2477
Author: anchal 
Type: DailyProgress 
Category: FSS 
Subject: FSS Diagnostics - Loop nonlinearity Test 

Method

I've wrote this script, nonlinTF.py which controls a Marconi 2023A and SR785 together. Marconi is used to providing a carrier frequency which is mixed with the Source Out signal from SR785 before feeding into the TEST2 input port on D040105 of TTFSS boxes. Then OUT1 port on D040105 of TTFSS box is used to read back at channel two of SR785 (channel one being fed with a copy of the Source Out signal). So SR785 is effectively measuring any downconversion in the loop (due to some nonlinearity) from micing of CF-IF, CF and CF+IF probe signals injected into the loop. The effectively closed-loop transfer function between TEST2 and OUT1 should be G/(1+G), so this injected signal should not suffer any suppression, nor should it affect the locks. The locks were maintained without any problems during the whole measurement. The CF frequency was stepped by 100 kHz from 100kHz to 10 MHz and then by 1 Mhz upto 100 MHz.

Mixer ZX05-1LHW (level +13 dBm) was used for the mixing and IF peak voltage was set to 30 mV. The configuration of the measurement for the transfer function is present in the configuration file in the folder.

Results?

  • I had to upload plots in png as they were aggregated result of a lot of data, pdf would have been very heavy.
  • North Side looks good with only minor bumps in 60 Hz harmonics. I'm not even sure if this just came because of SR785.
  • The South side however looks very dramatic. A lot of stuff happening when carrier frequency was near 50 MHz.
  • But I'm not sure if this measurement even makes any sense. South side is better in performance then North side, this wasn't expected.
  • Also, the measurements are long-time measurements, so a lot of things could have changed between North and South (they were taken on different days too).
  • I'll take more verifying measurements near the suspected frequencies tomorrow.
  • I'm also thinking of taking spectrums instead of swept sine transfer functions next time.

Data

Attachment 1: NFSS_NonLinearity_Test.png  251 kB  | Hide | Hide all
NFSS_NonLinearity_Test.png
Attachment 2: SFSS_NonLinearity_Test.png  247 kB  | Hide | Hide all
SFSS_NonLinearity_Test.png
Attachment 3: signal-attachment-2019-11-09-195635.jpeg  1.955 MB  | Hide | Hide all
signal-attachment-2019-11-09-195635.jpeg
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