[PD] butterworth filter
matju at artengine.ca
Thu Oct 26 21:44:27 CEST 2006
On Thu, 26 Oct 2006, Pall Thayer wrote:
> Yeah, I thought about that but does one then set each of the lop~'s for
> 10Hz or try to spread the 10 between them like:
> [lop~ 2.5]*4 or [lop~ 10]*4
You want to cut at 10 Hz so you put four of them at 10 Hz.
Each linear filter has a fixed gain for each frequency. The log-log
spectrum of one filter drops suddenly around 10 Hz with a straight slope.
With several filters in series, the log-log spectra add up, so the slope
I suppose that you've seen log-log graphs before? for a function y=f(x),
they have log(y) and log(x) axes, instead of y and x axes.
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| Mathieu Bouchard - tél:+1.514.383.3801 - http://artengine.ca/matju
| Freelance Digital Arts Engineer, Montréal QC Canada
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