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xenquan - RF Cafe Forums
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| xenquan
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Post subject: xenquan
Posted: Mon Sep 05, 2005 9:38 pm
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Joined: Mon Sep 05, 2005
9:32 pm
Posts: 1 |
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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!
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Post subject:
Posted: Tue Sep 06, 2005 4:29 am
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maxwell |
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Post subject:
Posted: Tue Sep 06, 2005 9:06 am
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| Captain |
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Joined: Mon Sep 01, 2003
6:59 pm
Posts: 22
Location: Boston
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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
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Posted 11/12/2012
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