Electronics World articles Popular Electronics articles QST articles Radio & TV News articles Radio-Craft articles Radio-Electronics articles Short Wave Craft articles Wireless World articles Google Search of RF Cafe website Sitemap Electronics Equations Mathematics Equations Equations physics Manufacturers & distributors Engineer Jobs LinkedIn Crosswords Engineering Humor Kirt's Cogitations RF Engineering Quizzes Notable Quotes Calculators Education Engineering Magazine Articles Engineering software RF Cafe Archives RF Cascade Workbook 2018 RF Symbols for Visio - Word Advertising RF Cafe Forums Magazine Sponsor RF Cafe RF Electronics Symbols for Visio RF Electronics Symbols for Office Word RF Electronics Stencils for Visio Sponsor Links Saturday Evening Post NEETS EW Radar Handbook Microwave Museum About RF Cafe Aegis Power Systems Anritsu Alliance Test Equipment Amplifier Solutions Anatech Electronics Axiom Test Equipment Berkeley Nucleonics Bittele Centric RF Conduct RF Copper Mountain Technologies Empower RF everything RF Exodus Advanced Communications Innovative Power Products ISOTEC KR Filters Lotus Systems PCB Directory Rigol RF Superstore San Francisco Circuits Reactel RFCT TotalTemp Technologies Triad RF Systems Windfreak Technologies Withwave LadyBug Technologies Wireless Telecom Group Sponsorship Rates RF Cafe Software Resources Vintage Magazines Thank you for visiting RF Cafe!
Exodus Advanced Communications Best in Class RF Amplifier SSPAs - RF Cafe

P1dB definition - RF Cafe Forums

RF Cafe Forums closed its virtual doors in 2010 mainly due to other social media platforms dominating public commenting venues. RF Cafe Forums began sometime around August of 2003 and was quite well-attended for many years. By 2010, Facebook and Twitter were overwhelmingly dominating online personal interaction, and RF Cafe Forums activity dropped off precipitously. Regardless, there are still lots of great posts in the archive that ware worth looking at. Below are the old forum threads, including responses to the original posts.

NOTICE: The original RF Cafe Forum is available again for reading, and the new RF Cafe Blog is an active board.

-- Amateur Radio

-- Anecdotes, Gripes, & Humor

-- Antennas

-- CAE, CAD, & Software

-- Circuits & Components

-- Employment & Interviews

-- Miscellany

-- Swap Shop

-- Systems

-- Test & Measurement

-- Webmaster


Post subject: P1dB definition Posted: Mon May 18, 2009 9:31 am


Joined: Wed Aug 16, 2006 8:20 am

Posts: 23

Location: India


In the data-sheets the P1dB for an amplifier or mixer is defined for at single frequencies. Take the case of a UWB signal of say 500 MHz bandwidth centered at an LO signal of 4.9 GHz where have a power distribution such that all frequencies component from 4.65 GHz to 5.15 GHz have same amplitude level. Consider that the amplitude levels are just below the P1dB rating at the respective frequencies for a given amplifier.

my question is

1. Will the device saturate?

2. If yes then how do we find the maximum power that can be applied to the device input before it reaches saturation in the presence of such a signal?


Ashish Bondia,

Design Engineer- RF



Post subject: Re: P1dB definitionPosted: Mon May 18, 2009 8:23 pm

Site Admin

Joined: Mon Jun 27, 2005 2:02 pm

Posts: 373

Location: Germany


P1dB by definition is frequency selective, that means it is defined only per single frequency. If you want to know the P1dB characterstic of your amplifier for a wide band of frequencies, you have to measure it for each frequency.

If your BW is very wide, you can measure the P1dB for small frequency spacings and assuming that the device's flatness is relatively small, you can interpolate the P1dB for the frequencies in between.

saturation occurs after P1dB has been reached.

There is a term called back off, which is defined as

Backoff= P1dB(in)-Pin(actual)


P1dB(in) - is the P1dB level at the input (measured).

Pin(actual) - actual provided input power.

If the backoff which you get is positive, then you are away from P1dB and therefore far from saturation.


Best regards,

- IR



Post subject: Re: P1dB definitionPosted: Tue May 19, 2009 10:56 am


Joined: Thu Sep 25, 2003 1:19 am

Posts: 50

Location: texarcana

Is it possble to add the tone power to LOG(N).?

N= number of channels

Posted  11/12/2012

Boonton RF Power Measurement
ConductRF Phased Matched RF Cables - RF Cafe
withwave microwave devices - RF Cafe
RF Cascade Workbook 2018 by RF Cafe
Copper Mountain Technologies (VNA) - RF Cafe

Please Support RF Cafe by purchasing my  ridiculously low−priced products, all of which I created.

These Are Available for Free


About RF Cafe

Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024


    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 World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while tying up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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: