[AMRadio] AM power

[Geoff Edmonson]

On 06/18/2011 09:47 PM, Gary Schafer wrote:
> It doesn't matter what the modulation is. Single tone, two tone or voice.
> 100% positive modulation of a 375 watt carrier still comes out to 1500 watts
> PEP.
>

100%, yes.  But, if you've -got- natural asymmetrical audio coming out 
of your mouth, and your speech equipment, from the microphone through 
the modulator, to where the positive peaks have a Symmetry Ratio of 3 or 
4, then keeping the PEP level DOWN to 1500w, means reducing the carrier 
by 100 or more watts.  So, in order to keep at 1500w PEP, if I have an 
SR of 4, that means 100w of carrier gives me a PEP reading of 1600w.

100% symmetrical audio is an SR of 2.  An SR of 3 means the positive 
peaks are reaching 3 to 1 on the scope, where the negative peaks are not 
pinching off the carrier.  If you start with a 100w carrer, then an SR 
of 2 = 400wpep.  The same 100w carrier with an SR of 3 = 800w PEP.  An 
SR of 4 is 1600w PEP output.