[SI-LIST] AW: Re: DC data

... and add something to your signal.
Good filters do that with amplitude much below the amplitude of interest.
But imagine a simple rectangular window, this is equal to convolute your signal 
with sin(x)/x, a strong ringing and non causal function. You would add 
non-causality to your signal and ringing.


regards
Andreas

-----Ursprüngliche Nachricht-----
Von: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] Im 
Auftrag von Andrew Ingraham
Gesendet: Dienstag, 23. Juni 2009 19:31
An: si-list
Betreff: [SI-LIST] Re: DC data

> How can I get a smooth clean sinusoidal curve.

Of course you can filter data and end up with a pure sine wave, if that's
what you really want.  So if you absolutely need a sinusoidal curve as your
result, a lowpass or bandpass filter might do that.

(Or you could just create one mathematically and ignore the measured data.)

Any time you apply filtering, you are throwing away something, whether it is
other signals, noise, or a phase shift or modulation of the signal.  You
need to understand how your processing affects your results.

Andy

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