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Entry  Thu May 12 23:50:10 2011, Suresh, Update, RF System, POY55_Demod board Hardware change completed 
    Reply  Wed May 18 07:18:15 2011, Suresh, Update, RF System, POY55_Demod board Hardware change completed 
Message ID: 4708     Entry time: Thu May 12 23:50:10 2011     Reply to this: 4737
Author: Suresh 
Type: Update 
Category: RF System 
Subject: POY55_Demod board Hardware change completed 

The Demod board with S. No. 022 (being used earlier as REFL11) has been modified.  It now has SCLF-65 as its input LP filter on the PD input line and a PQW-2-90 power splitter.  The unit functioning okay (I and Q signals are 90 deg apart.

The loss of Q output was traced to a possible loose solder joint and we now have both the I and Q signals after resoldering all components in the vicinity of U7 (Ref Schematic of D990511)

There is a strong oscillation around 350Hz present on I and Q signals of both REFL55_Demod and POY55_Demod.  Don't know the source. 

We have run out of power splitters to continue with the Demod board modification. We do not currently have an AS11_Demod board.  All the others are in place and ready for the I<->Q phase angle measurement.

In summary we now have the following Demod boards in place:

[ REFL11, POY11, REFL55, AS55, POY55, POY22, POY110]_Demod

 

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