FIR Filter design tool

Hi,

Is there any free or low cost software tools that could calculate FIR
filter coefficients for bandpass filter? 

Thanks!

Yes,

Try here: http://personal.atl.bellsouth.net/p/h/physics/Fir.zip

I posted the directions a couple of weeks ago. When I'm back at the
house, I'll try to encapsulate some directions with the program.

Clay

Try with Filter express which is freely available.

I like Meteor: http://www.nyx.net/~wliu/filter.html.  The interface is
klunky, but it does a superb job at optimization.  I've used it before
with excellent results.

"Brian Neunaber" <neunaber@gmail.com> wrote in message 
news:1122651140.442066.137580@g49g2000cwa.googlegroups.com...
>I like Meteor: http://www.nyx.net/~wliu/filter.html.  The interface is
> klunky, but it does a superb job at optimization.  I've used it before
> with excellent results.

The original Parks-McClellan Fortran program is simple to use and you don't 
have to compile it for Windows as there's an executable here:

ftp://mission-systems-inc.com/outgoing/Parks_McClellan/

The band edges are defined as fractions of the sample rate - so should not 
be entered for values greater than 0.5.
The main thing it doesn't take as an input is a variable weight function in 
each band for passband/stopband filters.  But a constant weight for each 
band is usually plenty good so you can trade between ripples in each band.
The wider the transistion bands (which are between each pair of band edges) 
the smaller the ripple for a given length.

Example input and output for a bandpass filter:

What is the length of the filter?
64

Type?: 1 - Passband/Stopband
2 - Differentiator
3 - Hilbert Transformer
1

How many pass bands and stop bands?
3

List band edges, one per line or comma delimited
0,.2,.25,.3,.35,.5

List filter response for each band, one per line or comma delimited
or desired slop if a differentiator
0,1,0

List filter weight for each band, one per line or comma deliminted
for a differentiator, a single weight will be used as w/f
1,1,1

1**********************************************************************

                         FINITE IMPULSE RESPONSE (FIR)
                         LINEAR PHASE DIGITAL FILTER DESIGN
                         REMEZ EXCHANGE ALGORITHM

                         BANDPASS FILTER

               FILTER LENGTH =  64

               ***** IMPULSE RESPONSE *****
                    H(  1) =  0.30537898E-03 = H(  64)
                    H(  2) =  0.49959793E-03 = H(  63)
                    H(  3) =  0.23405663E-03 = H(  62)
                    H(  4) =  0.79011120E-03 = H(  61)
                    H(  5) = -0.22296710E-02 = H(  60)
                    H(  6) = -0.76272665E-03 = H(  59)
                    H(  7) =  0.46930313E-02 = H(  58)
                    H(  8) = -0.48358738E-03 = H(  57)
                    H(  9) = -0.58953944E-02 = H(  56)
                    H( 10) =  0.22085404E-02 = H(  55)
                    H( 11) =  0.35657433E-02 = H(  54)
                    H( 12) = -0.99933892E-03 = H(  53)
                    H( 13) =  0.15462588E-02 = H(  52)
                    H( 14) = -0.62719714E-02 = H(  51)
                    H( 15) = -0.49136356E-02 = H(  50)
                    H( 16) =  0.18144451E-01 = H(  49)
                    H( 17) =  0.17707171E-02 = H(  48)
                    H( 18) = -0.26896507E-01 = H(  47)
                    H( 19) =  0.65720053E-02 = H(  46)
                    H( 20) =  0.23222979E-01 = H(  45)
                    H( 21) = -0.96453326E-02 = H(  44)
                    H( 22) = -0.53003971E-02 = H(  43)
                    H( 23) = -0.69127390E-02 = H(  42)
                    H( 24) = -0.15373212E-01 = H(  41)
                    H( 25) =  0.49446747E-01 = H(  40)
                    H( 26) =  0.18551089E-01 = H(  39)
                    H( 27) = -0.10686837E+00 = H(  38)
                    H( 28) =  0.10605872E-01 = H(  37)
                    H( 29) =  0.15323216E+00 = H(  36)
                    H( 30) = -0.67921862E-01 = H(  35)
                    H( 31) = -0.16304862E+00 = H(  34)
                    H( 32) =  0.12894705E+00 = H(  33)

                        BAND  1        BAND  2        BAND  3        BAND
  LOWER BAND EDGE    0.000000000    0.250000000    0.349999994
  UPPER BAND EDGE    0.200000003    0.300000012    0.500000000
  DESIRED VALUE      0.000000000    1.000000000    0.000000000
  WEIGHTING          1.000000000    1.000000000    1.000000000
  DEVIATION          0.001624721    0.001624721    0.001624721
  DEVIATION IN DB  -55.784420013  -55.784420013  -55.784420013

  EXTREMAL FREQUENCIES
     0.0000000   0.0156250   0.0322266   0.0478516   0.0644531
     0.0800781   0.0966797   0.1123047   0.1279297   0.1435547
     0.1591797   0.1728516   0.1865234   0.1962891   0.2000000
     0.2500000   0.2539062   0.2626953   0.2753906   0.2871094
     0.2958984   0.3000000   0.3500000   0.3539062   0.3636719
     0.3773437   0.3919922   0.4076172   0.4242187   0.4408203
     0.4574219   0.4740234   0.4916016

 **********************************************************************

Fred