# IP3 Narrowband Versus Wideband- RF Cafe Forums

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

Post subject: IP3 narrowband versus wideband Posted: Fri Oct 26, 2007 6:28 pm

Lieutenant

Joined: Fri Oct 26, 2007 5:29 pm
Posts: 2
I have measured the IP3 point of an amplifier with a narrowband signal.

Is there a formula which takes into account the bandwidth of the signal. Is it simply IP3 + 10 log (BWratio)?

Top

IR
Post subject: Posted: Sat Oct 27, 2007 8:05 am

Joined: Mon Jun 27, 2005 2:02 pm
Posts: 373
Location: Germany
As far as I know there is no formula that takes into consideration the BW of the signal.

According to the IEEE, the space between the 2 tones should be up to
+/-5% of the carrier or the middle frequency of operation.

Top

RFDave
Post subject: Posted: Sun Oct 28, 2007 8:20 pm

Captain

Joined: Sat Apr 22, 2006 11:14 pm
Posts: 10
The intercept point is defined as a combination of single tones, so there really isn't a wideband equivalent. I've read several papers about modeling wideband signals with multiple tones (Dr. Gard @ NC State has some good papers on this), so people are looking at that. In this case, you are looking at combinations of IP3/IP5/IP7, and spectral regrowth is generally what's its referred as.

If you are looking at wideband separation of tones (2 tones separated at several MHz), then the relative phasing of the 2F1-F2 and 2F2-F1 terms can lead to asymmetry on the high side and low side tones.

Dave

Posted  11/12/2012

RF Cafe Software

Wireless System Designer

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

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 !