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Entry  Wed Apr 27 15:34:38 2011, kiwamu, Update, Electronics, AS55 demod board with new 90 deg splitter : healthy 
    Reply  Wed Apr 27 17:38:01 2011, kiwamu, Update, Electronics, Re : AS55 demod board with new 90 deg splitter : healthy relativephase.pngIQamplitude.png
Message ID: 4573     Entry time: Wed Apr 27 17:38:01 2011     In reply to: 4572
Author: kiwamu 
Type: Update 
Category: Electronics 
Subject: Re : AS55 demod board with new 90 deg splitter : healthy 

relativephase.png

Figure.1  I-Q relative phase measurement as a function of LO power.

 Blue curve : relative phase of AS55 that I have modified today (#4572).

 Red curve : relative phase of AS11 that I had modified a week ago (#4554). Just for comparison.

 The relative phase of AS55 agrees approximately what we expected according to the datasheet of PSCQ-2-51W. We expected 85 degree.

 

IQamplitude.png

Figure.1  I-Q amplitude imbalance as a function of LO power.

From - 5 dBm to 5 dBm in LO power the imbalance is within 3 %.

But the precision of the measurement is also about 2 % (because I used an oscilloscope). Even so the imbalance is still good.

Quote from #4572

Some plots will be posted later.

 

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