Thread Subject: Creation of simple HF filter...

Hallo!

Could you help me please to create a simple HF filter in
Matlab with the following frequency characteristic:

K(w)= A/(B+jw), where A and B real constants, j - imaginary
unit, w - circular frequency...

Thank you in advace for quick and clear help...

Check out FDATool

Srikanth <skt@xdtech.com> wrote in message
<95574cbf-da3b-4a76-8184-9a6fc0dd9e34@e6g2000prf.googlegroups.com>...
> Check out FDATool

Thank you for answer...
I don't see a way to create a custom filter such as in my
first post by means of fdatool... Just predefined ones...

Your formulation K(w)= A/(B+jw) looks like a time-continous
filter. What exactly do you want to do with it? Basically
Matlab knows discrete signals and filters like K(exp(jw)) =
A/(B+exp(-jw)).

Markus

"Markus Buehren" <mb_matlab.REMOVE@gmxTHIS.de> wrote in
message <fn312m$hsd$1@fred.mathworks.com>...
> Your formulation K(w)= A/(B+jw) looks like a time-continous
> filter. What exactly do you want to do with it? Basically
> Matlab knows discrete signals and filters like K(exp(jw)) =
> A/(B+exp(-jw)).
>
> Markus

Markus,

I need to create a discrete analogue for time-continous
filter K(w)= A/(B+jw). I suppose the discrete filter will
act with discrete signal like its analog prototype acts with
continous signal...

Is it possible to make one at all?

Your filter is a first order butterworth filter. This is found in
FDATool, and there are other commands as well for it (lookfor
butterworth).
hth
ss

On Jan 21, 11:37 pm, "Andrey Kazak" <A...@nospam.ru> wrote:
> "Markus Buehren" <mb_matlab.REM...@gmxTHIS.de> wrote in
> message <fn312m$hs...@fred.mathworks.com>...
>
> > Your formulation K(w)= A/(B+jw) looks like a time-continous
> > filter. What exactly do you want to do with it? Basically
> > Matlab knows discrete signals and filters like K(exp(jw)) =
> > A/(B+exp(-jw)).
>
> > Markus
>
> Markus,
>
> I need to create a discrete analogue for time-continous
> filter K(w)= A/(B+jw). I suppose the discrete filter will
> act with discrete signal like its analog prototype acts with
> continous signal...
>
> Is it possible to make one at all?

Srikanth <skt@xdtech.com> wrote in message
<647bcf3c-a3e0-4f90-9628-b5d83e28e9db@e23g2000prf.googlegroups.com>...
> Your filter is a first order butterworth filter. This is
found in
> FDATool, and there are other commands as well for it (lookfor
> butterworth).
> hth
> ss
>
> On Jan 21, 11:37 pm, "Andrey Kazak" <A...@nospam.ru> wrote:
> > "Markus Buehren" <mb_matlab.REM...@gmxTHIS.de> wrote in
> > message <fn312m$hs...@fred.mathworks.com>...
> >
> > > Your formulation K(w)= A/(B+jw) looks like a
time-continous
> > > filter. What exactly do you want to do with it? Basically
> > > Matlab knows discrete signals and filters like
K(exp(jw)) =
> > > A/(B+exp(-jw)).
> >
> > > Markus
> >
> > Markus,
> >
> > I need to create a discrete analogue for time-continous
> > filter K(w)= A/(B+jw). I suppose the discrete filter will
> > act with discrete signal like its analog prototype acts with
> > continous signal...
> >
> > Is it possible to make one at all?
>

help bilinear

you already have the simple poles and zeros of the analog
filter and only need the sample rate to convert these to a
digital filter.

> help bilinear
>
> you already have the simple poles and zeros of the analog
> filter and only need the sample rate to convert these to a
> digital filter.

Ok!

As I understood, for my filter I need to use the following
syntax of "bilinear":

[numd,dend] = bilinear(num,den,fs)

for my filter it's:

[numd,dend] = bilinear([A],[1 B],fs)

Is it right?

What should I do with [numd,dend] to perform a filtration?

Help me please...