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Entry  Fri Apr 15 12:17:39 2011, kiwamu, Update, LSC, 11MHz demod board : funny I-Q phase relativephase.png
    Reply  Fri Apr 15 15:15:08 2011, kiwamu, Update, LSC, 11MHz demod board : 90 degree splitter 
       Reply  Sat Apr 16 02:00:14 2011, rana, Update, LSC, 11MHz demod board : 90 degree splitter 
          Reply  Mon Apr 18 13:05:57 2011, kiwamu, Summary, LSC, demod board modification demod_board.png
             Reply  Mon Apr 18 14:11:44 2011, kiwamu, Update, LSC, RF status RF_Work_Status.png
             Reply  Thu Apr 21 21:24:41 2011, kiwamu, Update, LSC, demod board : new 90 deg splitter DSC_2949_ss.jpgDSC_2951.JPGDSC_2952_ss.jpg
                Reply  Thu Apr 21 21:46:22 2011, kiwamu, Update, LSC, demod board : new 90 deg splitter relativephase.png
                   Reply  Fri Apr 22 11:08:50 2011, kiwamu, Update, LSC, demod board AS11 : amplitude imbalance IQamplitude.png
Message ID: 4555     Entry time: Thu Apr 21 21:46:22 2011     In reply to: 4554     Reply to this: 4560
Author: kiwamu 
Type: Update 
Category: LSC 
Subject: demod board : new 90 deg splitter 

A less LO power dependence on the relative phase was found. The new 90 deg splitter works better.

From -3 dBm to 10 dBm in LO power, the relative phase is within 90 +/- 5 deg.

As a comparison I plot the phase that I measured when the handmade coil had been there (green curve in the plot).

relativephase.png

 

 I will also measure amplitude unbalances between I and Q.

Quote from #4554

A 90 degree splitter, PSCQ-2-51W, has arrived today and I installed it on a demod board called AS11.

Results of the I-Q phase measurement with the new splitter will be reported soon.

 

 

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