[AMRadio] Re: AMRadio Digest, Vol 39, Issue 28


D. Chester k4kyv at charter.net
Sat Apr 7 04:48:56 EDT 2007


>> Uh... 'wastes time with the carrier'?

What 'wastes time with the carrier' is the pseudo-AM that consists of one 
sideband plus carrier.

That is  NOT the same thing as AM.  It is merely SSB with poor carrier 
suppression.

One sideband plus carrier has "quadrature distortion" when received with an 
envelope detector.  The only way to avoid this is to run a  low percentage 
of modulation.  With DSB plus carrier (conventional AM), the quadrature 
distortion from each of the two sidebands cancels that of the other, and you 
receive distortion free audio (theoretically).

One sideband plus reduced carrier may be useful, since the "pilot" carrier 
can be used as a reference for the receiver to lock onto.  This is often 
done in commercial communication circuits.

But one sideband with full carrier is an extremely poor way to transmit 
"AM".

IMO, it is a total waste of time, energy and tube life to transmit in that 
mode.

Don k4kyv




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