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Spectrum Analyzer Measurement-How to set the RBW&VBW - RF Cafe
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| Simon
Liu |
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Post subject: Spectrum Analyzer Measurement-How to set the RBW&VBW
Posted: Wed Jan 19, 2005 1:33 am
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| Captain |
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Joined: Wed Jan 05, 2005
2:20 am
Posts: 9
Location: BeiJing,China
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Hi , I am a new RF engineer. As we known,
when testing the isolation or Xth harmonic by spectrum
analyzer,we need to set the poper RBW and VBW.Also
they will effect on the sweep time.My question is
do we have a standard to sepcify how to set the
RBW&VBW since different RBW will result in different
test result. Is there anyone could provide the App
note for me?
Thanks
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Kirt Blattenberger
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Post subject:
Posted: Wed Jan 19, 2005 11:44 pm
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| Site Admin |
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Joined: Sun Aug 03, 2003
2:02 pm
Posts: 451
Location: Erie, PA
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Greetings Simon: When making a measurement
to determine conformance to a particular specification
(GSM, for example), the spec normally dictates the
bandwidth in which it is to be measured. Otherwise,
you have to rely on experience and knowledge of
how the RBW (resolution bandwidth) and VBW (video
bandwidth) affect the displayed signal. Most spectrum
analyzers come with a user’s guide that provides
some insight into how to set the instrument. There
are some good test notes on the RF Cafe “Test Notes”
page (1), including the classic from HP (now Agilent).
The subject is too broad to cover here, so please
read some of the notes on that page. One rule of
thumb to remember is that if a signal amplitude
varies as you change the RBW, then it has some bandwidth
to it (not a pure tome as with a synthesizer), and
if it does vary with RBW, then it has some bandwidth
(either noise or signal width). (1)
http://www.rfcafe.com/references/test-notes.htm
- Kirt Blattenberger
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Simon Liu |
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Post subject:
Posted: Thu Jan 20, 2005 9:44 pm
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Joined: Wed Jan 05, 2005
2:20 am
Posts: 9
Location: BeiJing,China
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Guest |
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Post subject:
Posted: Wed Feb 09, 2005 5:15 pm
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You'll also want to pay attention to the input power.
Most HP SA's are NF limited below -21dBm and IM
limited above -21dBm.
That probably the most
common mistake (incorrect attenuation) I have seen
with users new to the spectrum analzer.
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Posted 11/12/2012
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