•−•  ••−•    −•−•  •−  ••−•  •
RF Cafe Morse Code >Hear It<

Job Board

About RF Cafe™

Sitemap

>10,000 Unique Pages!

RF Cafe Software

RF Cascade Worbook
 RF Cascade Workbook 2005 - RF Cafe
Calculator Workbook
RF Workbench
Smith Chart™ for Visio
Smith Chart™ for Excel
RF & EE Symbols Word
RF Stencils for Visio

Your RF Cafe
Progenitor & Webmaster

Click here to read about RF CafeKirt Blattenberger
BSEE
KB3UON
EIEIO

Carpe Diem!
(Seize the Day!)

5th MOB:
My USAF radar shop

Airplanes and Rockets:
My personal hobby website

Equine Kingdom:
My daughter Sally's horse riding website

  Spectrum Analyzer Measurement-How to set the RBW&VBW - RF Cafe Forums

The original RF Cafe Forums were shut down in late 2012 due to maintenance issues. Below are all of the old forum threads, including all the responses to the original posts.

-- Amateur Radio
-- Anecdotes, Gripes & Humor
-- Antennas
-- CAE, CAD, & Software
-- Circuits & Components
-- Employment & Interviews
-- Miscellany
-- Swap Shop
-- Systems
-- Test & Measurement
-- Webmaster

 Post subject: Spectrum Analyzer Measurement-How to set the RBW&VBW
Posted: Wed Jan 19, 2005 1:33 am 
 
Captain
User avatar

Joined: Wed Jan 05, 2005 2:20 am
Posts: 9
Location: BeiJing,China
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?
:idea: :?: :!: ;-)

Thanks


 
   
 
 Post subject:
Posted: Wed Jan 19, 2005 11:44 pm 
 
Site Admin
User avatar

Joined: Sun Aug 03, 2003 2:02 pm
Posts: 451
Location: Erie, PA
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 :smt024


 
   
 
 Post subject:
Posted: Thu Jan 20, 2005 9:44 pm 
 
Captain
User avatar

Joined: Wed Jan 05, 2005 2:20 am
Posts: 9
Location: BeiJing,China
Got it.
Thanks man!
Simon


 
   
 
 Post subject:
Posted: Wed Feb 09, 2005 5:15 pm 
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.




Posted  11/12/2012

SEARCH More Than 10,000 Pages Indexed on RF Cafe

Copyright 1996 - 2016
Webmaster:  Kirt Blattenberger, BSEE - KB3UON
Family Websites:  Airplanes and Rockets | Equine Kingdom

All trademarks, copyrights, patents, and other rights of ownership to images
and text used on the RF Cafe website are hereby acknowledged.