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!

Peak Power Detector Circuit - 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


mmaassel
Post subject: Peak Power Detector Circuit Posted: Sun May 14, 2006 10:44 pm

Colonel


Joined: Mon Apr 10, 2006 12:43 pm
Posts: 25
Good day. I am looking for information on peak power detectors.

It is my understanding that what makes a peak detector work is more of a timing issue then anything else. For example the burst of RF energy that needs to be measured is about 5 mS in length with a 100 mS off time between bursts. Now the detector does not have a long time constant (the response time of the diode is on the order of 100 nS). So the ADC needs a trigger to begin conversion when there is an RF signal present.

Is this the basic premise of a peak power detector? Any additional information would be appreciated.

Thank you
Michael


Top

fred47
Post subject: Peak power detectorPosted: Tue May 16, 2006 6:38 pm

General


Joined: Wed Feb 22, 2006 3:51 pm
Posts: 104
Hi!

There are some assumptions in your posting that I'd like to clarify.

1. The output of the peak detector must be a digital word, with enough bits (whatever that is).
2. The signal you're working with is a pulse, or pulse-like.
3. The timing of the presentation of the ADC output bits isn't particularly important (in other words, the signal's amplitude is slowly varying, if it changes at all).
4. You're interested in pulse-to-pulse variation (perhaps?)

Peak power detectors are often implemented in analog circuitry, where time constants, pulse widths, pulse repetition rates, etc have a distinct bearing on circuit designs.

Good Luck!
Fred


Top

mmaassel
Post subject: Peak power detectorPosted: Thu May 18, 2006 10:27 am

Colonel


Joined: Mon Apr 10, 2006 12:43 pm
Posts: 25
Good day Fred. Thank you for your response.

For right now, I am looking for some general information about how to design a peak power detector.

Let me restate my position to help clarify what I am talking about.

I will have an RF signal that is pulsed. I need to be able to measure the power for each pulse. I have made a couple of assumptions that might be my problems

Assumptions:
1) The response time of the detector is fast enough (for example 5 uS) and the pulse width is sufficient large (5 mS) so that there is no problem with the detector responding to the signal.

2) The output of the peak detector needs to go to an embedded processor so I need an analog-to-digital convertor.

3) The ADC I am using is fast enough (conversion time of 5 to 10 uS) that I do not need to worry about a sample & hold circuit>

Based on these assumptions, it is my understanding that I would need to somehow trigger the ADC at the correct time to get an accurate power reading.

Are my assumptions valid?

Fred - if you have some additonal information about designing peak detectors (websites, books, magazines, etc) I would very much appreciate any information you can provide.

Thank you for your time and help.
Michael


Top

languer
Post subject: Posted: Sat May 20, 2006 4:37 am

Captain


Joined: Sun May 14, 2006 8:53 pm
Posts: 17
Location: Earth
Take a look at Analog Devices' website (RMS detectors and log-amps). The following linkcontains very good documentation.


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