Thank you for visiting RF Cafe! Electronics World Cover,TOC,and list of posted Popular Electronics articles QST Radio & TV News Radio-Craft Radio-Electronics Short Wave Craft Wireless World About RF Cafe RF Cafe Homepage RF Cafe in Morse Code Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs Twitter LinkedIn Crosswords Engineering Humor Kirt's Cogitations Engineering Event Calendar RF Engineering Quizzes AN/MPN-14 Radar 5CCG Notable Quotes App Notes Calculators Education Magazines Software,T-Shirts,Coffee Mugs Articles - submitted by RF Cafe visitors Simulators Technical Writings RF Cafe Archives Test Notes Wireless System Designer RF Stencils for Visio Shapes for Word Search RF Cafe Sitemap Advertising Facebook RF Cafe Forums RF Cafe Homepage Thank you for visiting RF Cafe!

Number of Points, if Bandwidth, Sweep Time ? - RF Cafe Forums

The original RF Cafe Forums were shut down in late 2012 due to maintenance issues. Original posts:

Amateur Radio | Antennas | Circuits & Components | Systems | Test & Measurement


mbergmann
 Post subject: Number of points, if bandwidth, sweep time ?
Posted: Tue Jun 20, 2006 5:14 am 
 
Captain

Joined: Mon Jun 19, 2006 10:27 am
Posts: 13
Hello,

can anyone please explain to me, the relationship between
- number of points
- if bandwidth
- sweep time ?

For example, how do I know which bandwidth I need if the number of points and sweep time are given ?


 
   
 
Kirt Blattenberger
 Post subject:
Posted: Tue Jun 20, 2006 9:57 am 
 
Site Admin
User avatar

Joined: Sun Aug 03, 2003 2:02 pm
Posts: 476
Location: Erie, PA
Greetings mbergmann:

The relationship varies with each instrument. The usuer's guide usually provides a formula and/or table, such as Table 15-3 (page 149) in this Agilent manual for the ESA and PSA series spectrum analyzers. There are relational formulas throughout the programming examples.

http://cp.literature.agilent.com/litweb ... -90482.pdf

_________________
- Kirt Blattenberger :smt024
RF Cafe Progenitor & Webmaster


 
   
 
mbergmann
 Post subject:
Posted: Wed Jun 21, 2006 7:55 am 
 
Captain

Joined: Mon Jun 19, 2006 10:27 am
Posts: 13
Thanks Kirt for your answer, but does it really depend on the instrument ?

An explanation is given on
http://ku-prism.org/video/JohnPaden/network_analyzer_oper.htm
http://ku-prism.org/update/SummerSeminar/MrPaden.html

According to this, the number of points is determined by the maximum length of the impulse response and the bandwidth of measurement:
number of points = length of impulse response * bandwidth of measurement
First of all I don't understand this simple formula, secondly how do I know the impulse response of my DUT ? Generally, that's unknown I would say.

The necessary IF bandwidth is determined by the desired dynamic range (SNR).

Finally, the sweep rate is calculated by the bandwidth, number of points and group delay through the IF BW-filter (approximately the reciprocal value of the chosen IF BW). The sweep rate, together with the length of the impulse response results in the change in frequency during the impulse response, which must be lower than the IF bandwidth ("the sweep time is always okay if you are properly sampling the frequency domain!").






Posted  11/12/2012

RF Cafe Software

   Wireless System Designer - RF Cafe
Wireless System Designer

RF & EE Symbols Word
RF Stencils for Visio
Calculator Workbook
RF Workbench
Smith Chartâ„¢ for Visio
Smith Chartâ„¢ for Excel

About RF Cafe

Kirt Blattenberger - RF Cafe WebmasterCopyright
1996 - 2022
Webmaster:
Kirt Blattenberger,
 BSEE - KB3UON

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The Internet was still largely an unknown entity at the time and not much was available in the form of WYSIWYG ...

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

My Hobby Website:
 AirplanesAndRockets.com

Try Using SEARCH
to Find What You Need. 
There are 1,000s of Pages Indexed on RF Cafe !

height-line