> Now, recall this started with a class C amplifier,
> so a bit of inexpensive Digital Signal Processing
> (DSP) will necessarily be inserted between the mike
> and the exciter to provide for envelope restoration
> (linearization) of the amplifier via the PWM
> modulator. The exciter will only be required to
> provide around 30 watts drive for this scheme to
> function. Note that the exciter must be operated
> without compression, limiting, or ALC in this system.
> Those functions may be included in the DSP section.
I think you'd need a feedback system - polar or cartesian loop,
for example. The AM/PM in the output stage will be severe, and
probably beyond simple pre-correction in open loop.
You can buy the whole feedback system integrated on a single chip
these days, but all the uses I'm aware of are VHF and higher so I
don't know if it will work at HF.
Steve
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|