Re: IIR band pass filter design query

On Wed, 29 Aug 2007 07:03:36 -0500, srikk123 wrote:

Hi,

i have to design a digital Band pass filter using butter worth
4th order filter.... the requirement is that the pass band frequency is

1KHz and the sampling frequency is 48KHz. the filter should have a very

high Q factor...no band is specified as such

my question is

1. Q factor is related to analog filter and how is it translated to
digital filter design
2. what is the best Q factor that could be got and how to measure it
3. any matlab functions to implement it like butter()

any other related material would be good...

thanks
--srikk

The term "Q factor" applies much more to 2nd-order sections; for
multi-pole filters the term is "shape factor". The shape factor of a
filter is the ratio between the 3dB (or 6dB) bandwidth and the 60dB (or
sometimes 40dB) bandwidth. I've never seen the term applied to a
discrete-time filter, but who knows?

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
.

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