Switched mode RF amplifiers

If the output is a passive tuned network, the switching element can just go hard on/off at the RF input rate, namely make a square wave, so no sampling is involved.

In a way, that *is* sampling at twice the RF rate. It's just that each sample lasts half an RF period.

I'm not sure what the OP is trying to do.

Jeroen Belleman

A normal Class C RF amolifier kicks the output tuned circuit once per cycle, just at the output frequency rate.

The trick is that the amplifier does not attempt to preserve the incoming waveform, only just the frequency.

But that works (without additional tricks) only for signals with a constant amplitude, like FM.

For use with AM, RF amplifiers that use higher sampling frequencies are used.

Linear amplification is a different beast. For linear amplification, simple RF amplifiers need to run Class B, AB or A.

There are ways to run a switching amplifier (Class C, Class E and friends) on all kinds of higher modulations, above AM. Google for EER amplifier (Envelope Erasure and Restoration). The requirement is to control the supply feed with the desird output envelope.

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** Think Jeroen just proved that chalk and cheese are the same.

Anyone wanna Chalk Burger ?

..... Phil

That is what I mean with "additional tricks". Things like HELAPS.