Re: Calc. energy harmonics

On Nov 11, 11:40 pm, Jim Slatter <jimslat...@xxxxxxxxxxxxx> wrote:
For example, an RF fundamental and the frequency obtained by dividing
it in successively in two 20 or 30 times.

Thank you,

Jim Slatter

Wouldn't that depend on the shape of the waveform?

Indeed it does. Pure sine waves, for example, have no harmonics. A
distorted sine wave has harmonics proportional to the percentage of
distortion.

Harry C.

I am referring to a "resonant" frequency irrespective of waveform.
Here is a specific example. I have two separate signals of equal
amplitude. One is a 1GHz sinewave, the other is 1GHz divided by 2
twenty times to produce a distant lower octave.

How do I calculate the _proportion_ of energy density of the distant
octave compared to that of the fundamental, assuming all else is
equal?

Jim Slatter

Jim, if you have no harmonics, meaning that you are dealing with
perfect sine waves at their fundamental frequenceis, the result is
found of combining these two frequencies is found in very old and
classic modulation theory generally described in texts on modulation
theory. . Energy density is comparared in proption to the energy power
db ratio of the two signals. This is very basic EE comunications
technology so there is little need to complicate it. The energy
density ratio is simply equal to the power density radio of the two
signals, which are normally compared in terns if the db content.

I agree that this can be confusing to the non-engineer/scientist, but
it it actually a rather trivial concept once digested. Still first,
you have to grasp the difference between dbs expessed as 10 log v1/v2,
and those expessed as 20 log P1/P2. Once you grasp this, the rest
become trivial.

When you get into harmonics, things become much more complex, but you
first have to realize that a pure sine wave has no harmonics.

EE's know this, and so do physicists. It' basic knowledge.

So long as you are dealing with pure sine wave sources, the solution
becomes trivial. When you delve into distorted sine waves, the
solution becomes much more complex..and accordingly more interesting.

I personally like to play with pipe organ design, where except for a
perfect flute pipe (whose sound I find as boring as listening to the
amplified output of my amplified Genrad audio oscillator), and hence
love the complex harmonic relationship that exists withing a full
chorus of diapasons (who's output is anything but sine waves.) is to
me incredible. You've heard it, and I can only describe it as a
somewhat "granular sound", which is very difficult to electronically
duplicate.

Ok, that gets into entirely different material, which can consume
hours of endless discussion...between musicians and physicists.

If you want to discuss this person to person, my email is actually
hhc3141@xxxxxxxxxx Not the email address that I post under.

Harry C.









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