Greetings All, Anybody know how to implement non symmetric filter with park mcclelans. For instance, the firpm() (as far as my knowledge goes) outputs symetric filters with even or odd symmetry depending on the Order of the filter. Any suggestion or link is appreciated. Thanx, chivak
non symmetric filter using park mcclelans
Started by ●June 12, 2008
Reply by ●June 12, 20082008-06-12
chivak wrote:> Greetings All, > > Anybody know how to implement non symmetric filter with park > mcclelans.There is no such thing. The symmetry is required for the Parks-McClellan algorithm. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●June 12, 20082008-06-12
On Thu, 12 Jun 2008 02:12:09 -0500, "chivak" <cd_prasad@hotmail.com> wrote:> > Greetings All, > > Anybody know how to implement non symmetric filter with park >mcclelans. > > For instance, the firpm() (as far as my knowledge goes) outputs symetric >filters with even or odd symmetry depending on the Order of the filter. > > Any suggestion or link is appreciated.http://www.dspguru.com/comp.dsp/tricks/dsn/nlp_fir.htm Eric Jacobsen Minister of Algorithms Abineau Communications http://www.ericjacobsen.org Blog: http://www.dsprelated.com/blogs-1/hf/Eric_Jacobsen.php
Reply by ●June 12, 20082008-06-12
Eric Jacobsen wrote:>> Anybody know how to implement non symmetric filter with park >>mcclelans. >> > http://www.dspguru.com/comp.dsp/tricks/dsn/nlp_fir.htm >Designing Re and Im parts separately is the neat trick, however the resultant filter will be neither equiripple nor optimal. VLV
Reply by ●June 12, 20082008-06-12
On Thu, 12 Jun 2008 13:48:18 -0500, Vladimir Vassilevsky <antispam_bogus@hotmail.com> wrote:> > >Eric Jacobsen wrote: > >>> Anybody know how to implement non symmetric filter with park >>>mcclelans. >>> >> http://www.dspguru.com/comp.dsp/tricks/dsn/nlp_fir.htm >> > >Designing Re and Im parts separately is the neat trick, however the >resultant filter will be neither equiripple nor optimal. > >VLVThere are limitations to any method, of course, but the OP didn't ask for equiripple or optimal, just a method using P-M. Eric Jacobsen Minister of Algorithms Abineau Communications http://www.ericjacobsen.org Blog: http://www.dsprelated.com/blogs-1/hf/Eric_Jacobsen.php
Reply by ●June 12, 20082008-06-12
>On Thu, 12 Jun 2008 13:48:18 -0500, Vladimir Vassilevsky ><antispam_bogus@hotmail.com> wrote: > >> >> >>Eric Jacobsen wrote: >> >>>> Anybody know how to implement non symmetric filter with park >>>>mcclelans. >>>> >>> http://www.dspguru.com/comp.dsp/tricks/dsn/nlp_fir.htm >>> >> >>Designing Re and Im parts separately is the neat trick, however the >>resultant filter will be neither equiripple nor optimal. >> >>VLV > >There are limitations to any method, of course, but the OP didn't ask >for equiripple or optimal, just a method using P-M. > > > >Eric Jacobsen >Minister of Algorithms >Abineau Communications >http://www.ericjacobsen.org > >Blog: http://www.dsprelated.com/blogs-1/hf/Eric_Jacobsen.php >Thanx for pointing me to the link. I needed a filter like this for phase equlization application. Will try it out. -Chivak
Reply by ●June 13, 20082008-06-13
On Thu, 12 Jun 2008 02:12:09 -0500, "chivak" <cd_prasad@hotmail.com> wrote:> > Greetings All, > > Anybody know how to implement non symmetric filter with park >mcclelans. > > For instance, the firpm() (as far as my knowledge goes) outputs symetric >filters with even or odd symmetry depending on the Order of the filter. > > Any suggestion or link is appreciated. > > Thanx, > chivakHi, I was wonderin'. Do you really want a non-symmetric (nonlinear phase) FIR filter? I ask that because the advantage of FIR filters is that they are linear phase when their coefficients are symmetric. The disadvantage of FIR filters is that they require more computations (per filter output sample) than nonlinear phase IIR filters. Wouldn't it be better for you to use an IIR filter? Just wonderin'. [-Rick-]
Reply by ●June 13, 20082008-06-13
"Eric Jacobsen" <eric.jacobsen@ieee.org> wrote in message news:var2545aoc7gjtip8pdoh4btb5grphelf5@4ax.com...> On Thu, 12 Jun 2008 02:12:09 -0500, "chivak" <cd_prasad@hotmail.com> > http://www.dspguru.com/comp.dsp/tricks/dsn/nlp_fir.htm > > Eric Jacobsen > Minister of Algorithms > Abineau Communications > http://www.ericjacobsen.org > > Blog: http://www.dsprelated.com/blogs-1/hf/Eric_Jacobsen.phpEric, I'm embarrassed to note that I'd seen *dsprelated* mentioned many times but had never checked it out. Very nice! Was it done from scratch or did you use a tool or a service provider / toolset? Chivak, There *is* an equiripple method that has been mentioned many times. Due to Hermann and Schussler: http://groups.google.com/group/comp.dsp/browse_thread/thread/fb7ce6e2467cc661/d1cd98ed7d49f158?lnk=gst&q=Hermann+Schussler#d1cd98ed7d49f158 I hope this helps. If you search comp.dsp for [Hermann Schussler] then you will find a number of treatments and related tricks. Fred
Reply by ●June 13, 20082008-06-13
Rick Lyons wrote:> I was wonderin'. Do you really want a > non-symmetric (nonlinear phase) FIR filter? > I ask that because the advantage of FIR filters > is that they are linear phase when their > coefficients are symmetric. The disadvantage > of FIR filters is that they require more computations > (per filter output sample) than nonlinear phase > IIR filters. > Wouldn't it be better for you to use an IIR filter? > Just wonderin'.There are systematic methods for designing FIR filter to an arbitrary response, and the FIR doesn't have to be linear phase. There are no such methods for IIRs. Hence in some cases the non-symmetric FIR could be very convenient. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●June 13, 20082008-06-13
On Jun 13, 8:32 am, Vladimir Vassilevsky <antispam_bo...@hotmail.com> wrote:> ... > There are systematic methods for designing FIR filter to an arbitrary > response, and the FIR doesn't have to be linear phase. There are no such > methods for IIRs. Hence in some cases the non-symmetric FIR could be > very convenient. > > Vladimir Vassilevsky > DSP and Mixed Signal Design Consultanthttp://www.abvolt.comSee author = "Ricardo A. Vargas and C. Sidney Burrus", title = "On the Design of L_p IIR Filters with Arbitrary Frequency Response", url = "citeseer.ist.psu.edu/663472.html" } And Matlab's iirlpnorm Dale B. Dalrymple http://dbdimages.com
