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: <email@example.com>
- 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