Modulation impact when amplifying a DSB signal?

[Bill Fuqua]

     In an old very radio handbook there was a high-level SSB generator. It 
used two pairs of 807's as two balanced modulators and both screen 
modulated.  The screen modulators were fed by an audio phase shift network 
and the balanced modulators were fed in quadrature.
     Also,  I don't know how much efficiency advantage plate modulation has 
over  lower level modulation with a linear amplifier.
Sure the class c amplifier can will operate from 75 to as much as 90 
percent efficiency but the modulator still is limited to
67% or so and you have all those filaments to heat.  Plate modulated class 
C amplifier system will be more efficient but
not a whole lot more overall, at least during steady modulation  during 
music programs etc.

73
Bill wa4lav


At 06:13 PM 2/15/2009 -0500, kd4e wrote:
>Simple = grids & screens push-pull, plates parallel.
>
>Perhaps using a single dual pentode tube, 6AR11.
>
>
> >> I am thinking of this in terms of a QRP DSB exciter using low plate
> >> voltage (125v) versus having to manage modulation at a higher power stage.
> >>
> >
> > I'm a bit confused here.  Generating clean DSB with suppressed
> > carrier requires a fair amount of circuitry.  If you really want
> > AM (DSB plus carrier), why not modulate at the milliwatt level
> > with something like a cathode modulator or the output-transformer
> > scheme used in Clegg 22ers and follow it with class-A linear
> > stages up to the 5-watt level.
> >
> > Jim Bromley, K7JEB
> >
>
>--
>
>Thanks! & 73, doc, KD4E
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