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Entry  Wed Apr 22 11:48:30 2015, manasa, Summary, General, Delay line frequency discriminator for FOL error signal 
    Reply  Wed Apr 22 14:56:18 2015, manasa, Summary, General, Delay line frequency discriminator for FOL error signal 
       Reply  Mon May 4 10:21:09 2015, manasa, Summary, General, Delay line frequency discriminator for FOL error signal DFD.pngDFD_resp.png
       Reply  Mon May 4 12:42:34 2015, manasa, Summary, General, Delay line frequency discriminator for FOL error signal DFD_cosfit.png
          Reply  Mon May 18 14:46:20 2015, manasa, Summary, General, Delay line frequency discriminator for FOL error signal DFDnoise.pngDFDnoise_AC.pngFreqResp.pngDFD.zip
Message ID: 11270     Entry time: Mon May 4 10:21:09 2015     In reply to: 11236
Author: manasa 
Type: Summary 
Category: General 
Subject: Delay line frequency discriminator for FOL error signal 

Attached is the schematic of the analog DFD and the plot showing the zero-crossing for a delay line length of 27cm. The bandwidth for the linear output signal obtained roughly matches what is expected from the length difference (370MHz) .

We could use a smaller cable to further increase our bandwidth. I propose we use this analog DFD to determine the range at which the frequency counter needs to be set and then use the frequency counter readout as the error signal for FOL.

 

Attachment 1: DFD.png  35 kB  | Hide | Hide all
DFD.png
Attachment 2: DFD_resp.png  9 kB  | Hide | Hide all
DFD_resp.png
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