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Entry  Fri Apr 30 12:07:25 2021, aaron, DailyProgress, Laser, marconi locking 252D9563-0122-418B-9B97-29D44FEF83E9.jpeg
    Reply  Fri Apr 30 15:15:33 2021, rana, DailyProgress, Laser, marconi locking 
       Reply  Mon May 3 23:28:56 2021, rana, DailyProgress, Laser, delay line frequency discriminator DFD.jpg
          Reply  Wed May 5 11:54:19 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 9x
             Reply  Wed May 5 22:21:17 2021, rana, DailyProgress, General, delay line frequency discriminator 
             Reply  Thu May 6 10:48:40 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 3EFFFA27-AAF6-434F-A1AB-FE7C657A464C.jpegDL_3CH.pdf
                Reply  Tue May 11 14:37:48 2021, aaron, DailyProgress, Laser, delay line frequency discriminator, current noise measurement 
                   Reply  Wed May 12 15:35:09 2021, aaron, DailyProgress, Laser, delay line in a box 69A8E6A2-7F85-464E-BDAA-8C6BBD2910B5.jpeg1D05A31E-7DBC-448B-A2F4-A8805EFAC393.jpeg25C2DD1E-7776-491E-BBCE-5F2D1EA935E3.jpeg
                   Reply  Wed May 12 16:52:08 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 3878D102-C5BB-46AE-B90B-540CFDE3100B.jpegSPSR785_NX_12-05-2021_173959.pdfSPSR785_SX_12-05-2021_183434.pdfSPSR785_NS_12-05-2021_191513.pdf
                      Reply  Thu May 13 16:31:40 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 6x
                         Reply  Thu May 13 19:09:16 2021, rana, DailyProgress, Laser, delay line frequency discriminator 
                         Reply  Fri May 14 18:43:25 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 994ECC7F-C5FE-4E7B-8F19-B1C118DCE6CE.png
                            Reply  Thu May 20 12:50:56 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 
                               Reply  Fri May 21 14:15:21 2021, aaron, DailyProgress, Laser, current noise of custom current drivers 5012D147-8B13-478C-BB83-57A71A2B304A.jpeg467DEC59-01B1-40CD-9F4E-4D9D87183A78.jpegABC2A51B-6726-4F9C-AD88-551ED7C90EEF.jpeg
                               Reply  Tue Aug 17 14:04:27 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 3A1E242C-F4F6-4A87-B2E8-E74839BE542C.jpeg
                                  Reply  Wed Aug 18 09:55:13 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 0A96102F-5465-456B-93BF-E2B9D4A7E96C.jpegtrim.2553D656-98A0-442D-9185-4C5252B2B727.MOVtrim.787F04FC-8DED-4501-B67D-FF98EC5D5D56.MOV
                                     Reply  Thu Aug 19 14:21:35 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 007FC2D7-F29B-4636-9CE7-04CBC3B789F7.jpeg1F1E68F0-199F-4E1C-B909-883A521E06CF.jpegScreenshot_from_2021-08-19_17-53-58.png
                                        Reply  Fri Aug 20 11:03:44 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 30A43669-5DFF-400A-BEB4-7EF71BBAE1A6.jpegA3BF5DA5-32E5-42A5-A1D8-9270C3D88518.pngScreenshot_from_2021-08-20_16-11-26.pngScreenshot_from_2021-08-20_16-20-48.png
                                           Reply  Mon Aug 23 13:38:57 2021, aaron, DailyProgress, Laser, delay line frequency discriminator Screenshot_from_2021-08-23_16-42-48.png
                                              Reply  Tue Aug 24 16:44:39 2021, aaron, DailyProgress, Laser, delay line frequency discriminator beats_regions.pdfTeraxion_noise.pdfEW_timeseries.pdf
                                                 Reply  Thu Aug 26 11:58:50 2021, aaron, DailyProgress, Laser, delay line frequency discriminator 9x
                                                    Reply  Fri Aug 27 15:27:38 2021, rana, DailyProgress, Laser, delay line frequency discriminator 
                                                    Reply  Tue Aug 31 15:14:28 2021, aaron, DailyProgress, Laser, quieting the Rio W and Teraxion beat notes, but not much help beats_regions_base2.pdfbeats_regions_base2.pdfTeraxion_noise_base2.jpgDLFD_foam.pdf
                                                       Reply  Wed Sep 1 12:20:18 2021, rana, DailyProgress, Laser, quieting the Rio W and Teraxion beat notes, but not much help 
                                     Reply  Thu Aug 19 16:32:47 2021, rana, DailyProgress, Laser, delay line frequency discriminator 
       Reply  Tue May 4 10:50:22 2021, aaron, DailyProgress, Laser, marconi locking 6DC5CB12-BCDF-4550-AFB8-42D3DC354AED.jpegSPSR785_04-05-2021_152326.pdf
          Reply  Wed May 5 00:27:10 2021, rana, DailyProgress, Laser, marconi locking 
Message ID: 2798     Entry time: Mon Aug 23 13:38:57 2021     In reply to: 2797     Reply to this: 2801
Author: aaron 
Type: DailyProgress 
Category: Laser 
Subject: delay line frequency discriminator 

cymac ADC noise

The noise I was seeing last week on the ADC did not show up when driving the same channels directly with a function generator, only when buffering the function through the SR560. Wrapping the BNC several times around a ferrite toroid between the SR560 and ADC reduces the noise to close to the level of the ADC noise floor (there is a < 5 count pkpk sine wave cross-coupled into the adjacent channels for a ~2000 count pkpk sine wave on the channel of interest, but the signal carrying channel itself looks clean).

The SR560 that was overloading on battery last week is now also overloading on line power. I've swapped it with one of our functioning SR560.

calibration

  • A 113.2 MHz sine from the Marconi nulls the output of the frequency discriminator, as measured by the G=1, DC-coupled SR560 sent to an oscilloscope.
    • At 113.2 MHz, a 314.2 Hz FM with 800 kHz deviation appears as a 1.24 mV sine wave on the G=10, AC-coupled SR560 (measured by an oscilloscope).
    • The DC-coupled SR560 has a 1 kHz lowpass filter, the AC-coupled has a 3 kHz lowpass filter (both 6 dB/oct)
  • I measured the noise level of the Marconi over several 10s of minutes (while trying to figure out how to use the calibration features of diaggui). The result is in attachment 1, with the y-axis still in units of 'counts / rtHz'.

delay line

Afterwards, I looked at the spectrum for the Rio E x Rio W laser beat note. Looked OK... there's some kind of filtering happening in my delay line though. If I watch the spectrum of the RF coupler's pickoff (1% between the amplifier and delay line box), the implied peak power entering the delay line box is ~ 5 dBm near any of the nulls (so ~113 MHz or 176 MHz), but over 15 dBm between the nulls. I hadn't noticed this behavior before (with the busted mixer and RF coupler before the amplifier).

Attachment 1: Screenshot_from_2021-08-23_16-42-48.png  23 kB  Uploaded Mon Aug 23 17:43:43 2021  | Hide | Hide all
Screenshot_from_2021-08-23_16-42-48.png
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