Marv,
> One of my favorite... hobbies.
>
> There is the original reference, "Single Sideband Transmission by
>Envelope Elimination and Restoration" by Leonard Kahn -- pp 803-806
>Proceedings of the IRE, July 1952
>
> A follow up article, "Comparison of Linear Single Sideband Transmitters
>with Envelope Elimination and Restoration Single Sideband Transmitters",
>by Kahn-- pp 1706-1712 Proceedings of the IRE, December 1956
>
> An article "The Envelope Elimination and Restoration Transmission
>System for SSB" by William Orr -- p14 CQ magazine, October 1972
>
> A mention of the technique in "High Efficiency RF Power Amplifiers" by
>Frederick Raab -- pp 8-29 Ham Radio, October 1974
>
> And a more contemporary article "Class-S High Efficiency Amplitude
>Modulator" by Raab -- pp 70-74 RF Design, May 1994 which also lists a
>number of modern references.
>
> You may also be interested in another technique for increased
>efficiency in a Class C stage described in a "New High-Efficiency 5KW AM
>Transmitter" by J.R. Skarbek -- pp8-13, Broadcast News, March 1960.
>
> Is this just research? Or are you thinking of building one?? :-)
Did Raab and his colleague ever publish their AM modulator design?
Fritz made several incorrect calculations in his previously published
work which my friend Peter G3YYN pointed out to him. Fritz wasn't too
forthcoming with information while we were building his class-E PA until
Peter threw those numbers back at him:-)
At the time, around a year or so ago he told us that he's built the
class-S Am modulator but had not got around to publishing his work.
Do you know more than us?
Yes, we are building one but will probably stick to regular PDM in the
modulator.
The PA is spot on the dime at 92% efficiency with a little over 100v on
the FET's.
Phil G4ZOW
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