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Entry  Thu Apr 28 15:23:11 2016, ericq, Update, LSC, Green PDH demod lowpass 
    Reply  Thu Apr 28 18:53:05 2016, rana, Update, LSC, Green PDH demod lowpass 
       Reply  Fri Apr 29 16:13:36 2016, ericq, Update, LSC, Green PDH demod lowpass IMG_3186.jpgpdh_lpf.pngelp_liso.zip
          Reply  Fri May 6 16:42:12 2016, ericq, Update, LSC, Green PDH demod lowpass pdh_lpf.pngAUX_X_PDH_OLG_May6.png
             Reply  Fri May 6 19:08:52 2016, rana, Update, LSC, Green PDH demod lowpass 
                Reply  Sat May 7 09:40:40 2016, ericq, Update, LSC, Green PDH demod lowpass 
                   Reply  Sun May 8 08:39:21 2016, rana, Update, LSC, Green PDH demod lowpass 
Message ID: 12110     Entry time: Fri May 6 16:42:12 2016     In reply to: 12101     Reply to this: 12111
Author: ericq 
Type: Update 
Category: LSC 
Subject: Green PDH demod lowpass 

I've build the filter, and it seems to have the desired TF shape.

I also re-purposed the 70k lowass to a ~120k lowpass by changing the 68nF caps to 22nF caps, since we still want some post-mixer rolloff. 

However, putting the ELPF in the chain caused some weird shapes in the OLG. I still need to get to the bottom of it. However, just with the post-mixer LPF modification, here's what the OLG looks like:

As Rana surmises, we definitely still add a boost and maintain a 10k UGF. I still need to look into the state of the remote boost....

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