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 Thank you for visiting RF Cafe!

Noise Figure Q - 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


James
Post subject: Noise figure Q.
Unread postPosted: Thu May 13, 2004 6:55 pm

If a filter has 1dB IL at ambient, the noise figure is 1dB. If at hot temperature, the filter has 1.5dB IL, will the NF be higher than 1.5dB?


Top


Guest
Post subject: Noise Figure will remain 1.5
Unread postPosted: Fri May 14, 2004 6:57 am

At higher temperature the overall noise power floor will be higher (KTB). However, noise figure is the ratio between the signal to noise ratio at the output to the signal to noise ratio at the input therefore the noise floor is cancelled out and what is left is the additive noise from the filter, or what you know as noise figure. In this case the additive noise is 1.5dB, which is the noise figure.


Top


Itay
Post subject: Correction to the formula
Unread postPosted: Fri May 14, 2004 10:48 am

Correction to the ratio you provided, the noise figure is the ratio between the S/N in the input to the one in the output.

Thanks,

Itay Reiss


Top


Tony Kurlovich
Post subject: Consider
Unread postPosted: Tue May 18, 2004 11:38 am

When NF is tested over temprature, is the ENR source in the chamber? Most people have it out side the chamber and NF is calculated based on an ambient reference temp.



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