Steve Thompson wrote:
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> Subject: [AMPS] 3/2 law, DAF, other musings
To: <amps@contesting.com>
> Date: Wednesday, March 22, 2000 9:58 AM
>
>
>
>
>
> Close in IMD is caused by odd order distortion an an amplifier
> characteristic. Even order (eg square law) produces IMD at harmonic
> frequencies, which get filtered out.
>
>
> Steve
>
However you need to ask yourself what happens to the even harmonic power
(energy) when it
arrives at the harmonic filter?
If the filter is an absorptive type then the vast majority gets dumped into a
resitive
load and is safely dissipated.
BUT very few harmonic filters are of the absorptive type.
The type most often used is a "reflective type" i.e. the energy is rejected by
the
filters reactive elements and returns to the source (the anode tank circuit).
Depending
on the phase and amplitude of these harmonic energies they can either add or
subtract
from the energy at the anode tank. It is quite possible to either increase or
decrease
the levels of odd order IMD products by this process. A trick which I have
demonstrated
to tech students many times!
Sure to start another argument!
Nomex Flame-proof overalls ON!
John ZS5JF
>
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