quantifying noise on a DC signal

Jul 21, 2011 32 Replies

Actually, noise is signal that you don't want. One might measure noise _amplitude_ as standard deviation, but one would measure noise _power_ (which makes more sense in a lot of ways) as variance.

But my real point is that unless you know what signal you want and what signal you don't, you are clueless as to what you can call noise and what you can call signal.

www.wescottdesign.com

"Phil Hobbs"

** Another insightless, pseudo academic twit with a giant opinion of himself.

Just like you.

.... Phil

What's the second harmonic of DC?

um... what's DC noise? Maybe you should think about what you wrote before you click the send button?

That's easy. The second harmonic is twice the fundamental. Let DimBulb do the math.

Never heard of offset? ;-)

Why Phil, how sweet of you. That's the nicest thing you've said to me all week.

Cheers

Phil Hobbs

He's still working on The Book. I think he'll be back once it's done.

John

Ah! Okey-dokey. I guess I'm not the only one who forgets to use the smiley face thing :-)

And my favorite: DIY projects!

Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------

On a sunny day (Fri, 22 Jul 2011 13:28:09 GMT) it happened snipped-for-privacy@puntnl.niks (Nico Coesel) wrote in :

You mean you have somebody else do the designs for you?

DIY = fix c.q. 'improve' your home

Failure does not prove something is impossible, failure simply indicates you are not using the right tools... nico@nctdevpuntnl (punt=.) --------------------------------------------------------------

On a sunny day (Fri, 22 Jul 2011 15:17:22 GMT) it happened snipped-for-privacy@puntnl.niks (Nico Coesel) wrote in :

Not always. Can be anything from cooking to cars to electronics to space photography.

It will take a model of the 'noise' (is it uncorrelated, white, or is it pickup of local radio signals?) as well as information on how the DAQ samples its inputs (what is the time aperture of a conversion?). The 'peak to peak' value is usually NOT given for white noise, so I'm thinking you have a pickup problem of some sort.

The urge to display the noise (basically, to put an error bar on your graph points) is noble, but it won't be easy.

you can't do that in real time, since it takes 100 sample chunks to get to where you wanted to be in the beginning.

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