Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2001
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2001

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: What is the difference equation of a Butterworth filter?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg27480] Re: What is the difference equation of a Butterworth filter?
  • From: "John Doty" <jpd at w-d.org>
  • Date: Tue, 27 Feb 2001 00:37:34 -0500 (EST)
  • References: <972ge7$4kr@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

In article <972ge7$4kr at smc.vnet.net>, "Elias Kyriakides"
<elias_kyriakides at hotmail.com> wrote:

> Can anybody provide me with the difference equation of a Butterworth
> filter? e.g. something like y[n] = a1x[n] +a2x[n-1] etc
> 
> Thanks, Elias
> 
> 

No. The Butterworth filter has a frequency response that is a rational
function of finite order. Such a response can be realized by differential
equations, but not by difference equations.

The Buttterworth filter is a classic utilizing the capabilities of analog
electronic components. Attempting to approximate it digitally probably
isn't a particularly useful exercise: digital filters have different
capabilities and limitations.

-- 
| John Doty		"You can't confuse me, that's my job."
| Home: jpd at w-d.org
| Work: jpd at space.mit.edu


  • Prev by Date: RE: interchange entries in list
  • Next by Date: Re: Integrate a matrix-function
  • Previous by thread: What is the difference equation of a Butterworth filter?
  • Next by thread: Interpreting InputForm[]