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 This message was sent using the Comp.DSP web interface on www.DSPRelated.com
IIR Filter fixed point DSP
Started by ●July 6, 2005
Reply by ●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 ●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. �����������������������������������������������������������������������
Reply by ●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 ●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 > > > > This message was sent using the Comp.DSP web interface on > www.DSPRelated.com