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Entry  Tue Mar 22 21:59:21 2011, tara, DailyProgress, Electronics Equipment, input refered noise for UPDH and sensing noise (RFPD) in ACAV PDHTF.pngnoise_raw.pngerrnoise.pngbeat_sensing.pngpeak_match.png
    Reply  Tue Mar 22 23:38:02 2011, Frank, DailyProgress, Electronics Equipment, input refered noise for UPDH and sensing noise (RFPD) in ACAV 
       Reply  Wed Mar 23 18:12:01 2011, tara, DailyProgress, Electronics Equipment, input refered noise for UPDH and sensing noise (RFPD) in ACAV electronic_noise.png000_0002.jpg000_0001.jpg000_0003.jpg
          Reply  Wed Mar 23 22:09:08 2011, Frank, DailyProgress, Electronics Equipment, input refered noise for UPDH and sensing noise (RFPD) in ACAV 
Message ID: 549     Entry time: Wed Mar 23 22:09:08 2011     In reply to: 548
Author: Frank 
Type: DailyProgress 
Category: Electronics Equipment 
Subject: input refered noise for UPDH and sensing noise (RFPD) in ACAV 

Ok, hmm,  still doesn't make sense. The first problem is that you don't have 50Ohm termination for the mixer signal when measuring with the scope, but if you connect it to the pdh box you have 50 Ohms. But that can't explain the plot alone.

Hmm, the amplifier might be a problem, it's a low-noise one but i didn't check the RF noise after installation. So remove the amplifier and redo the measurements. Be careful as the size of the error signal changes quite a lot and you have to turn the gain of the box back to 8 or so. So you have to re-measure everything.

 

 

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