In a message dated 09/03/2005 14:14:18 GMT Standard Time, firstname.lastname@example.org
The polar loop system is a variation of the DAF amplifier.
I think that there's a fundamental difference between the DAF and polar
loop. The major one is that polar loop has a negative feedback mechanism,
the DAF runs open loop.
Now if you modulated the supply volts to the Class E amplifier in sympathy
with the envelope so that it was always hard switching, you should be able to
keep the efficiency up. It would give an interesting problem in doing a
suitable switching modulator - by rule of thumb, I'd expect it to need a
of around 30kHz and a switching frequency in the hundreds of kHz, which
would be interesting EMC wise, too. Anything else and you'll lose efiiceincy.
Perhaps a better approach might be to use two Class E stages in a Callum
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