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xenquan - RF Cafe Forums

Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views. It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if you would like to post something on RF Cafe's Facebook page, please do.

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


 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

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