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!

Setup Question for Signal Source and Buffer - 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


Mr.Whatever
Post subject: Setup question for signal source and buffer Posted: Fri Oct 27, 2006 11:10 am

Captain


Joined: Fri Apr 07, 2006 6:10 pm
Posts: 18
I need your practical opinion from experience, if any. I have a signal source. Part of this signal needs to be sampled. One sampling process involves detecting whether the signal is there or not. Another sampling process will try to detect whether the signal amplitude has surpassed a certain threshold.

Just assume that the signal is a low frequency signal at 38 kHz.

Would it be optimal to do the following setup?

- use a quad opamp package and configure three of the opamps as voltage buffers / follower.
- tie the input of the three opamps to the same node
- connect the signal source to this common node

The first opamp would just replicate the signal source and send it unprocessed. The 2nd and 3rd opamp would do the sampling processing schemes.

Does this sound right?

Or would it be ok to skip the buffer setup and directly interface the signal source to a common bus that branches off directly to the sampling sections? This is assuming that the two sampling schemes utilize op amp inputs to do the signal detection and peak detection. Thanks!


Top

nubbage
Post subject: Posted: Fri Oct 27, 2006 11:22 am

General


Joined: Fri Feb 17, 2006 12:07 pm
Posts: 218
Location: London UK
At such a low frequency, I would have the first OA as a voltage follower/buffer.
The output would go to the second stage as a full-wave detector with a time constant well in excess of the carrier cycle time (ie LPF).
The output would split two ways.
One way to a Schnitt Trigger to act as the "Signal/NOT signal" output, with the trigger level set just above noise (assuming this level is predictable).
The second way would be to another Schmitt Trigger with an adjustable trigger threshold set to whatever level you are looking for.

If only we had a simple Drawing Tool.



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