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Entry  Tue Aug 16 16:59:20 2011, Anamaria, Update, RF System, AM in the PM 
    Reply  Wed Aug 17 02:48:56 2011, kiwamu, Update, RF System, Re: AM in the PM 
Message ID: 5249     Entry time: Tue Aug 16 16:59:20 2011     Reply to this: 5251
Author: Anamaria 
Type: Update 
Category: RF System 
Subject: AM in the PM 

Kiwamu, Keiko, Anamaria

Looking at the I and Q signals coming from REFL11 and REFL55 we saw large offsets, which would mean we have amplitude modulation, especially at 11MHz. We checked the PD themselves with RF spectrum analyzer, and at their frequencies we see stationary peaks (even if we look only at direct reflection from PRM). We changed the attenuation of the PSL EOM, and saw the peak go down. So first check is beam out of PSL EOM, to make sure the input beam is aligned to the crystal axis and is not giving AM modulation in adition to PM.

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