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40m Log |
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Tue Apr 24 11:31:59 2018, gautam, Configuration, ALS, Proposed changes to EX fiber coupling 
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Tue Apr 24 18:54:15 2018, gautam, Configuration, ALS, Proposed changes to EX fiber coupling
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Wed Apr 25 19:09:37 2018, gautam, Configuration, ALS, New look EX Fiber coupling    
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Thu Apr 26 11:24:50 2018, gautam, Configuration, ALS, New look EX Fiber coupling - pol stability
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Thu Apr 26 18:58:21 2018, Bruce, Configuration, ALS, New look EX Fiber coupling - pol stability
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Fri Apr 27 01:36:02 2018, gautam, Configuration, ALS, IR ALS noise performance    
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Wed May 2 21:39:33 2018, gautam, Configuration, ALS, IR ALS for EY
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Fri May 4 21:17:57 2018, gautam, Configuration, ALS, BeathMouth pulled out of PSL table
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Tue May 8 00:40:51 2018, gautam, Configuration, ALS, BeathMouth pulled out of PSL table 
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Thu May 24 19:41:28 2018, gautam, Configuration, ALS, BeathMouth reinstalled on PSL table
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Thu May 24 13:06:17 2018, gautam, Configuration, ALS, DFD noises 
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Thu May 24 20:31:03 2018, gautam, Configuration, ALS, DFD noises 
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Message ID: 13890
Entry time: Thu May 24 20:31:03 2018
In reply to: 13886
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Author: |
gautam |
Type: |
Configuration |
Category: |
ALS |
Subject: |
DFD noises |
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A couple of months ago, I took 21 measurements of the delay line transfer function. As shown in Attachment #2, the unwrapped phase is more consistent with a cable length closer to 45m rather than 50m (assuming speed of light is 0.75c in the cable, as the datasheet says it is).
Attachment #1 shows the TF magnitude for the same measurements. There are some ripples consistent with reflections, so something in this system is not impedance matched. I believe I used the same power splitter to split the RF source between delayed and undelayed paths to make these TFs as is used in the current DFD setup to split the RF beatnote.
Quote: |
I had made some TF measurements of the delay sometime ago, need to dig up the data and see what number that measurement yields.
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