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Thread: Marker Count Accuracy test failing


Permlink Replies: 2 - Pages: 1 - Last Post: Nov 11, 2011 11:37 AM Last Post By: tabbott
Tisfurs

Posts: 50
Registered: 01/20/09
Marker Count Accuracy test failing
Posted: Sep 20, 2011 2:31 PM
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Ok, I am calibrating an 8593E spectrum analyzer, with option 140. It is failing the Marker Count portion of its performance tests at 1.5GHz only with 20MHz and 1MHz spans. I have already verified the accuracy of the 10MHz reference and the 300MHz cal output. I have also already performed the Sampler Match adjustment. Any ideas how to fix this problem?
arxaa

Posts: 4
Registered: 11/11/11
Re: Marker Count Accuracy test failing
Posted: Nov 11, 2011 4:58 AM   in response to: Tisfurs in response to: Tisfurs
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I also have the same problem with two 8594E's. The marker count function reads wrong at the settings detailed in the calibration procedure, however it is possible to achieve a correct count by changing the reference levels and signal levels... This is the first time seeing this problem in many years of calibrating Agilent 8590 series spectrum analysers. Another 8594E tested yesterday counted perfectly at all times... Any assistance with this problem would be appreciated.
tabbott


Posts: 1,483
Registered: 07/24/09
Re: Marker Count Accuracy test failing
Posted: Nov 11, 2011 11:37 AM   in response to: Tisfurs in response to: Tisfurs
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Hi -

We’re going to have to answer a question with a question on this one.

Here it is:

With option 140, your analyzer has the precision frequency reference and the narrow resolution bandwidths. For the spans you’re testing; 20 MHz, 10 MHz and 1 MHz I do not believe the analyzer is even going into the narrow resolution bandwidths, which begin at 300 Hz and narrower. For these spans, my guess is the RBW is at 1 kHz or 3 kHz, so this issue is most likely not related to option 130, narrow resolution bandwidths.

What are your results at 20 MHz, 10 MHz and 1 MHz exactly? It sounded like the 10 MHz span was meeting spec.

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