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Entry  Thu May 6 16:18:37 2010, Alberto, Update, 40m Upgrading, New improved design for the 11MHz photodiode pox11.pdf
    Reply  Thu May 6 19:57:26 2010, Alberto, Update, 40m Upgrading, New improved design for the 11MHz photodiode pox11.pdf
       Reply  Fri May 7 11:21:49 2010, koji, Update, 40m Upgrading, New improved design for the 11MHz photodiode 
          Reply  Fri May 7 18:18:02 2010, Alberto, Update, 40m Upgrading, New improved design for the 11MHz photodiode 
             Reply  Fri May 7 19:02:27 2010, rana, Update, 40m Upgrading, New improved design for the 11MHz photodiode 
Message ID: 2897     Entry time: Fri May 7 19:02:27 2010     In reply to: 2896
Author: rana 
Type: Update 
Category: 40m Upgrading 
Subject: New improved design for the 11MHz photodiode 

To measure the width of a resonance, the standard method is to state the center frequency and the Q. Use the definition of Q from the Wikipedia.

As far as how much phase is OK, you should use the method that we discussed - think about the full closed loop system and try to write down how many things are effected by there being a phase slope around the modulation frequency. You should be able to calculate how this effects the error signal, noise, the loop shape, etc. Then consider what this RFPD will be used for and come up with some requirements.

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