(This is a correction to my previous note).
To those who say there is no such thing as RMS power, its time for you to go
back and re-learn your basic AC theory. RMS power is defined simply as the
time-average value of the energy in a circuit. There is much subtlety to what
is the appropriate time interval for this average, and causes most of the
confusion I see going on here.
In the practical world, RMS power is readily measured by a device (meter,
numerical integartor, etc.) that can measure the average value of V times I.
If the waveform is periodic, the average over many cycles approaches a
definite limiting value and this is referred to as the RMS power. If the
periodic waveform is also sinusoidal, this value will turn out to be (voila!)
.707(I) x .707(V)=.5VI where V<I are peak values. So for convenience, .707V
or I are referred to as the RMS values because they will properly calculate P
when used in P=VI.
Another not so well know fact is the actual measurments made by ordinary
voltmeters. When you measure an AC sinusoidal voltage with your Fluke or
Simpson260, what that instrument measures is actually the AVERAGE of V over a
half cycle, which is actually .626 Vpk. The scale of the meter is then
printed with a hidden scale factor of (.707/.626) so that a 1 volt sine-wave
will read 1 VAC. This calibration is ONLY valid for a sine-wave and other AC
waveforms will be read in error. For this reason, serious engineers also
possess and use "true RMS" meters which actually measure the avg. value of
Vsquared.
The problem with all of this discussion of SSB power is that the RF waveform
is madly varying on two different time scales: the RF carrer frequency and
the audio modulating frequency. In fact, your SSB transmitter with VOX input
does not have a well-defined average power of any kind. PEP is the true RMS
RF power over any time interval of several RF cycles (several microseconds )
But that average value will vary with the voice waveform and can be easily
averaged with an AF integrator driven by an RF RMS detector. That will give a
meaningful average power over millisecond time inervals, which is the best
you can hope for.
Eric von Valtier K8LV
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