On Sat, 15 Oct 2005 00:40:34 GMT, "W3JDR" wrote:

I understand the historical difficulties of making accurate RMS
measurements, however I didn't know the original post only solicited ways to
make the measurement with "current generation of commercial surplus
equipment ".

Hi Joe,

That was interjected by me, knowing the market of the past several
years being flooded after trunk systems began replacing older service.

My intention was to point out some measurement nuances that
might not be obvious at first glance.

Useful information, that.

Recently, it has become quite easy to do true RMS measurement at audio
frequencies using DSP techniques. In fact at audio you can even do an
accurate RMS measurement in DSP using a PIC microcontroller to sample the
signal and perform the calculations.

Yes, the miracle of Moore's law. 20 years ago I was with HP, here, to
help them introduce their 100KHz real-time dual channel audio spectrum
analyzer. That was a tremendous effort with a million lines of Pascal
code and 5 years in the making when most HP instrumentation hit the
market in 18 months from inception.

I got to know the range of FFTs under some of the most brilliant minds
on the topic. One, Nick Pendergrass, went on to teach at an eastern
university.

Today, it is an underclass topic, probably occupying no more than 6
weeks of instruction coupled to other interests. Still and all, I see
considerable errors of omission in the discussion. Such errors often
make the difference in delivering a serviceable performance compared
to that which is 100 times better (actually a million times, but few
could get their imagination around a number that big so I understate
it).

73's
Richard Clark, KB7QHC