Reply by Bob April 20, 20042004-04-20
Hello,

Yes, Mathlab supports it. Also, ONEoverT will implement cascade form IIR filter
very easily as well.

Bob Carter

loosepraje@yahoo.com (bngguy) wrote in message news:<519f37cf.0404191215.6760b325@posting.google.com>...
> hi! All, > i would like some info on implementing cascade form IIR > filters...does matlab support it???...as far as i can understand > butter,cheby1,cheby2,bessel,ellip generate coefficients in the direct > form...how do i implement the cascade form... > > TIA > bngguy
Reply by Jerry Avins April 19, 20042004-04-19
bngguy wrote:

> hi! All, > i would like some info on implementing cascade form IIR > filters...does matlab support it???...as far as i can understand > butter,cheby1,cheby2,bessel,ellip generate coefficients in the direct > form...how do i implement the cascade form... > > TIA > bngguy
"Cascade" refers to a chain of second-order sections. Sure, Matlab does that. Jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;
Reply by Jon Harris April 19, 20042004-04-19
Matlab generally refers to this as second order sections or SOS for short.
There are several functions in the SP toolbox that convert to/from the SOS form
including TF2SOS.

"Tim Wescott" <tim@wescottnospamdesign.com> wrote in message
news:1088dnid0eobb0b@corp.supernews.com...
> bngguy wrote: > > hi! All, > > i would like some info on implementing cascade form IIR > > filters...does matlab support it???...as far as i can understand > > butter,cheby1,cheby2,bessel,ellip generate coefficients in the direct > > form...how do i implement the cascade form... > > > > TIA > > bngguy > > I don't know if Matlab supports it, but cascading filters is relatively > easy. Here's the process I use: > > 1. Factor your numerator and denominator polynomials > 2. Combine all your complex pairs into 2nd-order polynomials > 3. Match zeros up to their closest denominators (I don't know the > "best" way to do this, use your intuition). > 4. Build as many 1st- and 2nd- order polynomials you need > 5. Check your gains from the input to the states, to verify > that nothing will overflow.
Reply by Tim Wescott April 19, 20042004-04-19
bngguy wrote:
> hi! All, > i would like some info on implementing cascade form IIR > filters...does matlab support it???...as far as i can understand > butter,cheby1,cheby2,bessel,ellip generate coefficients in the direct > form...how do i implement the cascade form... > > TIA > bngguy
I don't know if Matlab supports it, but cascading filters is relatively easy. Here's the process I use: 1. Factor your numerator and denominator polynomials 2. Combine all your complex pairs into 2nd-order polynomials 3. Match zeros up to their closest denominators (I don't know the "best" way to do this, use your intuition). 4. Build as many 1st- and 2nd- order polynomials you need 5. Check your gains from the input to the states, to verify that nothing will overflow. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com
Reply by bngguy April 19, 20042004-04-19
hi! All, 
        i would like some info on implementing cascade form IIR 
filters...does matlab support it???...as far as i can understand 
butter,cheby1,cheby2,bessel,ellip generate coefficients in the direct 
form...how do i implement the cascade form... 
 
TIA 
bngguy