Reply by adrian ●July 12, 20052005-07-12
http://www.winfilter.20m.com generates FIR/IIR in C code with float,
int8 or int16 coeffs.

maxascent wrote:

> Hi
>
> I am trying to design a IIR filter using a 16-bit fixed point DSP. I need
> to calculate the coeff in the form of second order sections. I would like
> to do this with MATLAB. Does anyone have some MATLAB code that will do
> this. I found a routine on Texas Instrument site but as well as the coeff
> it creates some scaling factors for the inputs. I dont want this as I have
> seen other programs such as Filter Express that just give the Coeff.
>
> Thanks
>
> J
>
>
>
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Reply by Chris Fogelklou ●July 11, 20052005-07-11
"maxascent" <johnbean_uk@hotmail.com> wrote in message 
news:ooOdnUULzZJTRVbfRVn-tw@giganews.com...

> Hi
>
> I am trying to design a IIR filter using a 16-bit fixed point DSP. I need
> to calculate the coeff in the form of second order sections. I would like
> to do this with MATLAB. Does anyone have some MATLAB code that will do
> this. I found a routine on Texas Instrument site but as well as the coeff
> it creates some scaling factors for the inputs. I dont want this as I have
> seen other programs such as Filter Express that just give the Coeff.
>


There is a function in Matlab called TF2SOS that converts any order IIR to 
second order sections.  Look up the help on that one...
Reply by Jerry Avins ●July 7, 20052005-07-07
Diego wrote:

> OK. You have several kinds of IIR filter, for instance elliptic (the
> better),  ...


Better for some uses, worse for others.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
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Reply by Diego ●July 7, 20052005-07-07
OK. You have several kinds of IIR filter, for instance elliptic (the
better), Chevishev, bessell, in matlab you can see the help there are
some examples
This is one matlab example:

For data sampled at 1000 Hz, design a sixth-order lowpass elliptic
filter with a cutoff frequency of 300 Hz, which corresponds to a
normalized value of 0.6, 3 dB of ripple in the passband, and 50 dB of
attenuation in the stopband:

[b,a] = ellip(6,3,50,300/500);

The filter's frequency response is freqz(b,a,512,1000)

title('n=6 Lowpass Elliptic Filter')

The coeffs are the array b and the array a.

Tou can see in matlab help typing IIR in the search box

Diego
Reply by maxascent ●July 6, 20052005-07-06
Hi

I am trying to design a IIR filter using a 16-bit fixed point DSP. I need
to calculate the coeff in the form of second order sections. I would like
to do this with MATLAB. Does anyone have some MATLAB code that will do
this. I found a routine on Texas Instrument site but as well as the coeff
it creates some scaling factors for the inputs. I dont want this as I have
seen other programs such as Filter Express that just give the Coeff.

Thanks

J 


		
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