get transfertfunction from fdesign.bandpass

Hello,

I was wondering if it is possible to get the transfertfunction that is used for the command fdesign.bandpass.

I know it is possible to get a transfert function with the butter command.

But the filters I get from the command butter are not stable when I use them in the digital filter in Simulink. Although (while using the same parameters) the fdesign.bandpass is!

So is it possible to genarate the transfert function from this fdesign.bandpass command?

[Salaheddin Hosseinzadeh]

It would be great if you could leave a comment or even share more of your experience, specially as I didn't provide a straight forward answer, I give you hints and you were smart enough to figure it out

Thanks.

Answer 1

[Salaheddin Hosseinzadeh]

There are some commands that transfer different parameters to transfer function such as

latc2tf
ss2tf
zp2tf
s2tf
sos2tf

After using fdesign.bandpass to specify your filter you have to use design to generaing the filter parameters, usually you will get the filter parameters in this step, like in case of a FIR lowpass you'll get the numerator, using one of the above I believe you cam get tp transfer function.

h=fdesign.bandpass(x y z w whatever);
hd=design(h,whatever);

hd should contain what u're looking for

[Salaheddin Hosseinzadeh]

It would be great if you could leave a comment or even share more of your experience, specially as I didn't provide a straight forward answer, I give you hints and you were smart enough to figure it out

Thanks.