<snip>
>Then it came to my mind that joining the two articles seems almost
>ideal: A class AB/F amp with ARF1500 MOSFETs would be free of
>hotspotting, because in the AB class it would run at very low
>voltage (20 or 30V at most) and above that it would be running class
>F. At the same time, the reduced dissipation goes a long way in
>helping with the cooling problem.
> The added complexity of the modulated switching power
>supply would be rewarded by the high efficiency. And the whole thing
>would still be small, lightweight and reasonably cheap. Any takers,
>out there?
>I would be really interested in knowing what you think of this. Am I
>a crazy dreamer (from reading too much 73) and just loosing my time,
>or do you see merits to this approach? Or do I come late, and
>someone has already done it?
>Manfred, XQ2FOD.
Hi Manfred,
There is a small problem, often overlooked, in the envelope
restored Class D/E/F "linear" scheme. The group delay through the
modulating path must be equal to the RF path delay for the system to
exhibit low distortion. This can be realized over a narrowband but,
when a wideband system is considered it may prove to be easier to
build an entire envelope restored transmitter than to construct a
standalone linear.
73 & Welcome to the group!
Marv WC6W
http://wc6w.50webs.com/
*
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