From: "Malcolm Watts"
Date: Wed, 16 May 2001 08:50:06 +1200
Subject: Re: [TSSP] Multimode CW excitation
Hi Paul,
The trick of splitting primary energy between two
resonators to obtain SQRT(2)V difference between them can be simply
done by using a second "passive" resonator as a ground mirror. I once
built a mini system to do it.
On 15 May 01, at 16:46, Paul wrote:
> Hi All,
>
> Just an off-the-cuff idea for your amusement,
>
> Say, P watts of CW base fed into a secondary gives a peak
> top volts V.
>
> Half that power, P/2 watts, would then give V/sqrt(2)
>
> Suppose you then setup a typical primary winding, resonated
> with the usual Cpri, but with the gap shorted. Modest k factor.
> Now the single mode splits into two, nearby frequencies,
> call them f+ and f-.
That assumes that there is an amplitude change (of course) and in the
normal course of events for that to occur, there is energy exchange
between the two resonant circuits at a rate dictated by k (I know you
know all this - just thinking aloud). But it is the effective
amplitude modulation of either circuit which when examined
spectrally, shows f+ and f- to be present (with no Fr). But in the
time domain, the resonator is still oscillating at Fr, albeit with a
sinusoidally varying amplitude. If I were to monitor an AM signal
from any source (or DSBSC to be more accurate), I would see the same
things in the frequency domain and the time domain. Anyway......
> Drive the base of the coupled system with P/2 watts at each
> resonance f+ and f-, for a total drive of P watts.
>
> Now, with the assumption that we still get V/sqrt(2) volts
> in each mode at the coil top, this means that (f+ - f-) times
> each second, the two modes reinforce at the top to give
> 2V/sqrt(2) volts, the net result being a peak voltage
> for our P watts which is sqrt(2) times that which we had with
> single mode CW excitation.
The two modes do not always reinforce though. they go through a cycle
which causes a peak coincidence at one point, and a cancellation at
another on a regular basis. Hence the amplitude modulation. Am I
reading your suggestion correctly?
> Then suppose we add a second 'primary' resonator...
>
> Cheers,
> --
> Paul Nicholson,
> Manchester, UK.
Regards,
Malcolm
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.