[Amps] Nonsense

[Steve Thompson]

On Thursday 16 May 2002 18:02, Maurizio Panicara wrote:
> Hi steve,
>
> there is no doubt that spurs or products of various type may be generated
> along a wide spectrum in the most strange or unpredictable ways, but no sub
> harmonic is existing in the strict sense, the term is not poor choice is
> totally unproper.
> I would like to know, it intrigues me very much, how to produce a real
> (true) frequency division using analog linear circuits and a sine wave
> carrier.
In linear circuits, I expect it's not possible, but few circuits are without 
non-linear aspects that become significant under some conditions. As best I 
remember the article I read, the argument goes that if anything (even noise, 
maybe) causes f/2 to appear in a circuit, then IMD between f/2 and f produces 
3f/2, then both f and 2f with 3f/2 produce f/2 and so on, so it can become 
stable and self sustaining if the circumstances are right. The same analysis 
can apply to f/3 etc. It's very common to find it when doing load pull tests 
on solid state PAs.

Steve


>
> 73,
> Mauri I4JMY
>
> > Perhaps 'sub harmonic' is a poor choice of term, but it's been in use as
>
> long
>
> > as I've been in the rf business to describe division products. In RF
>
> Design
>
> > some years ago there was a detailed article about the effect.
> >
> > Steve
>
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