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Re: Using Class C Amplifiers for SSB



on 1/2/01 3:21 AM, Hamish Moffatt at hamish@cloud.net.au wrote:

> On Tue, Jan 02, 2001 at 12:19:40AM -0600, Jon Ogden wrote:
>> Adding a modulated carrier (effectively not suppressing the carrier out of
>> your rig) to an SSB signal essentially makes it an AM signal.  After all the
> 
> [..]
> 
>> Now I suppose, you could insert an unmodulated carrier into your signal that
>> would in effect be a CW tone that is always there regardless of your
> 
> What makes one of these a modulated carrier and one unmodulated?

I was thinking about this some more and how this question might come up and
in looking further into this, perhaps I was not quite correct in my
terminology of calling it a "modulated" carrier.  In the first case of the
"modulated" carrier, your carrier and the audio signals are mixed resulting
in an output of the audio signal, your carrier and two sidebands.  In all
cases, the audio signal is filtered out and in the case of SSB, one of the
sidebands and the carrier are also removed.  Now the carrier and sidebands
have both a phase and frequency relationship.  To add a little "carrier" to
the signal, you'd simply decrease your carrier suppression.  Yes, the
carrier is the original signal, but it is related to the sideband.

In the second case I was speaking of, I was talking about adding an
unrelated CW tone to the output RF signal.  This could be done through a
combiner network.  Then one would think that this CW tone that's on all the
time would keep the class C amplifier biased on all the time.

That's the difference that I was speaking of.

But I don't think using either one with a class C amplifier would work in
either case.  

73,

Jon
NA9D

-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

"A life lived in fear is a life half lived."

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