You're correct, of course, Steve. I was thinking the average-responding
meter was calibrated to display average levels, but it is not: it is
calibrated to give the rms value of a true sine wave with that average
value. So the only way to measure the average value of a non-sinusoidal
ac signal is to use an average-responding meter and correct the
displayed reading as you have noted. Not relevant to the SINAD
discussion but interesting.

Thanks for the clarification.

Chuck

Steve Nosko wrote:
Nope. See my previous post.


A square wave has an average equal to the RMS equal to the peak. It's just
like DC.

The "older types" RESPOND to average of a SINE (63% of peak) but display the
value for the RMS (71% of peak), so they have a 1.11 correction factor to
get from average to RMS.

73, Steve, K,9.D;C'I


"chuck" wrote in message
ink.net...

Hello Owen,

Seems both average-responding and trms meters use rectifiers, so a
square wave input with perfect symmetry should result in BOTH meters
reading the same: an amount equal to the peak square wave voltage. Am I
confused on this?

Chuck

Owen Duffy wrote:

On Mon, 17 Oct 2005 03:09:11 GMT, Owen Duffy wrote:




So, theoretically:
- an ideal average responding meter should read (1-2/pi)% which is
36.3% or 8.8dB on an perfect square wave;


I think this is close to the right answer, but for the wrong reason. I
think it needs to be evaluated iteratively, and I get an answer closer
to 34.3% or 9.3dB.

Owen
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