MOTM

At 7:59 PM -0500 03/30/01, Tentochi wrote:
>>
>> Average and RMS usually mean the same thing, as RMS is a kind of average.
>> I think you meant to say peak and RMS.  Regardless, you don't
>> want the peak
>> to be too peak otherwise low frequencies will peek through.
>
>Actually, they are not the same thing and people often misuse
>the terms.  I guess you are directing your comments at Paul
>since it is he who wrote that though.
>
>I have included the mathematical difference which I can elaborate
>on from a mathematical perspective if needed.  There are several
>people here who I am sure can elaborate from electrical and audio
>perspectives.

You should know better than to have me do math :)  Anyway, RMS still is a
type of average -- that's what the "mean" in "root mean square" means.  I
wasn't trying to correct you, I was trying to understand the features you
were describing.

Anyway, you'll notice both equations are integrals taken over a certain
length of time.  I guess for a sine wave, that time can be one cycle giving
a "true" RMS value.  For audio, the longer the time the more average the
average, so my point was that time should be variable.  Afaik, even a peak
value is an average taken over a shorter period of time, otherwise it would
just be the rectified signal which would multiply the original signal in
the gain cell.

>This sounds stronger than I meant it to.  Sorry!!!  Too lazy
>to rewrite.

It's OK :)  I was just trying to clarify what you meant.