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!

Image Anf IF Rejection - 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

Post subject: Image anf IF rejection Posted: Thu Mar 23, 2006 1:24 pm


Joined: Wed Mar 08, 2006 8:18 am
Posts: 3
Guys - any idea on how to measure the image frequency and IF rejection ratio say your in band is 98MHz.



Post subject: Posted: Thu Mar 23, 2006 5:05 pm


Joined: Thu Sep 25, 2003 1:19 am
Posts: 50
Location: texarcana
Measure your desired IF signal. Apply the image frequency at the input and then measure the image IF.



Post subject: Image anf IF RejectionPosted: Fri Mar 24, 2006 11:18 am


Joined: Fri Feb 17, 2006 12:07 pm
Posts: 218
Location: London UK
More specifically if the IF is 10.7MHz, then set the sig gen to 98MHz and note a reference level immediately after the IF filter stage. Avoid taking a level any further down the IF chain, as the presumably FM receiver will have a nonlinear limiter.

Set the generator frequency to 21.4 MHz above or below the 98MHz channel, eg 76.6MHz and increase the level of the generator until it reaches the previous level. Note the attenuator level setting difference. This is the Image Rejection ratio in dB

Set the generator to 10.7MHz and repeat the measurement. The attenuator difference is the IF rejection.

All best


Post subject: Posted: Tue Apr 04, 2006 8:54 am


Joined: Wed Mar 08, 2006 8:18 am
Posts: 3
Thank you Guys.
I dont have the attenuator so this is what I did.
First measure the direct inject sensitivity at operating freq. and inject the image - the difference is my ratio. same thing on 10.7MHz for IF.

Thanks again.

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
Kirt Blattenberger,

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:

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