Thank you for visiting RF Cafe!

Your RF Cafe
Progenitor & Webmaster

Click here to read about RF CafeView the YouTube RF Cafe Intro VideoKirt Blattenberger
BSEE
KB3UON
EIEIO

Carpe Diem!
(Seize the Day!)

5th MOB:
My USAF radar shop

Airplanes and Rockets:
My personal hobby website

Equine Kingdom:
My daughter Sally's horse riding website

RF Cafe Software

Calculator Workbook
RF Workbench
Smith Chart™ for Visio
Smith Chart™ for Excel
RF & EE Symbols Word
RF Stencils for Visio

xenquan - RF Cafe Forums

The original RF Cafe Forums were shut down in late 2012 due to maintenance issues. Please visit the new and improved RF Cafe Forums that were created in September of 2015. Unlike with the old forums where users registered individually, the new forums use a common User Name and Password so anyone can post without needing to create an account. Please find the current User Name and Password on the RF Cafe homepage. Thanks for your participation.

Below are all of the old forum threads, including all the responses to the original posts.

-- Amateur Radio
-- Anecdotes, Gripes & Humor
-- Antennas
-- CAE, CAD, & Software
-- Circuits & Components
-- Employment & Interviews
-- Miscellany
-- Swap Shop
-- Systems
-- Test & Measurement
-- Webmaster

 Post subject: xenquan
Posted: Mon Sep 05, 2005 9:38 pm 
 
Lieutenant

Joined: Mon Sep 05, 2005 9:32 pm
Posts: 1
Hi All! I'm new to RF and electronics. WOuld like to ask you guys a very basic question that I couldn't get from internet. What is the difference between RF & CPU frequency? Does CPU frequency exhibit electromagnetic characteristics? Thnx!


 
   
 
 Post subject:
Posted: Tue Sep 06, 2005 4:29 am 
It all depends on which multimeter you use. ;-) 8) :x :P


 
  
 
 Post subject:
Posted: Tue Sep 06, 2005 9:06 am 
 
Captain
User avatar

Joined: Mon Sep 01, 2003 6:59 pm
Posts: 22
Location: Boston
xenquan,

RF, which stands for "radio frequency," does not really have a formal definiton for at which frequency it starts. Generally, anything above around 30 MHz is considered RF, but again, that's just some people's rule of thumb.

CPU frequencies are almost always a broad spectrum of frequencies created by the clocks driving the CPUs as well as all the internal frequencies created inside. Since all are rectangular in form, with vertical leading and trailing edges, odd harmonics of all the fundamentals are created with varying amplitudes. Add to that the mixing process that occurs due to nonlinearities in the circuitry, and you get a real mess of spectral noise. The higher the CPU frequency is, the worst it gets, usually.

Computer product vendors go to great trouble to shield their circuitry, and in fact are required by the FCC (in the U.S.) and CE (E.U.) to keep emissions below certain levels.

So, in answer to your question, yes, CPU frequencies are essentially RF.


Maxwell





Posted  11/12/2012
Copyright 1996 - 2016
Webmaster:  Kirt Blattenberger, BSEE - KB3UON

All trademarks, copyrights, patents, and other rights of ownership to images and text used on the RF Cafe website are hereby acknowledged.