Philip de Cadenet wrote:
Google does not turn up much when searching for the above.

I wonder if anyone can point me to any on-line references.

Specifically interested in HF circuit designs using switching FET's.

Tnx.

Look for class E. Class D describes an amplifier that switches faster
than the signal and has the output filtered to pass DC. Class E
describes an amplifier that switches _at_ the signal rate and has a
filter that has finite impedance at the fundamental and infinite
impedance at all the odd harmonics. The result is that the output
transistor drives a square-wave voltage and sees a sinusoidal current,
so all the power goes to the output with none wasted.

There have been articles in QEX and even QST -- they even explain what I
just said in sufficient detail to understand it.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com