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separating passband zeros and stopband zeros

Started by Appalayagari Sreedhar November 25, 2002
Hi,

I am working on the filter design,

i am designing the FIR filter,

i want to know exactly which zeros corresponds to passband and which zeros to
stopband.

how to get them

i can get the zeros all by using the command

tf2zp,

but i need to separete the passband and stopband zeros.

if anyone worked on this idea please send your valuable suggestions.

thanks in advance.

regds,sree.



An easy way is to do a pole zero plot using zplane.
If you are using one of the standard methods for
generating FIR filters 'fir1' 'fir2' 'firls' or
'cremez', the zeros directly on the unit circle are
the ones corresponding to the stop band. Also the
zeros on the real axis and left half of the plane
correspond to the stop band. Everything else is the
pass band. Note that under certain cases of
equiripple design some zeros on the real axis and the
left half of the plane may not conform to the above
rule.

Jatan
--- Appalayagari Sreedhar <> wrote:
> Hi,
>
> I am working on the filter design,
>
> i am designing the FIR filter,
>
> i want to know exactly which zeros corresponds to
> passband and which zeros to stopband.
>
> how to get them
>
> i can get the zeros all by using the command
>
> tf2zp,
>
> but i need to separete the passband and stopband
> zeros.
>
> if anyone worked on this idea please send your
> valuable suggestions.
>
> thanks in advance.
>
> regds,sree.


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