IIR filter stability issues

Started by Anonymous in comp.dsp14 years ago 12 replies

Hi, It would very helpful if someone could tell me how to test for the stability of an IIR filter.(i.e the stability problems related to...

Hi, It would very helpful if someone could tell me how to test for the stability of an IIR filter.(i.e the stability problems related to the implementation-due to availability of only finite precision) thanks srikar


IIR Filter fixed point DSP

Started by maxascent in comp.dsp14 years ago 4 replies

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...

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 a...


IIR filter on the dspic ... why does it not work properly

Started by Christian_ in comp.dsp14 years ago 3 replies

Hi, I am using an dsPic 2010 with an external A/D. I interface to the A/D via SPI. The A/D performs some filtering on its input (22 tap FIR). I...

Hi, I am using an dsPic 2010 with an external A/D. I interface to the A/D via SPI. The A/D performs some filtering on its input (22 tap FIR). I then do some more filtering on the dsPIC using the DSP library for the C30 complier. The filter I use is a IIR chebychev filter. Everything seems to work fine. The data coming from the A/D is pretty noise free due to the FIR and the additional IIR filteri...


adding up coefficients

Started by Gert Baars in comp.dsp14 years ago 4 replies

Hello, Recently I designed my first IIR filter from a 1st orde Butterworth. After implementation it works as it should. My second filter a...

Hello, Recently I designed my first IIR filter from a 1st orde Butterworth. After implementation it works as it should. My second filter a 2nd order Butterworth is ready on paper. What occured to me is when I add up the coefficients from the 1st order filter the sum = 1. Surprisingly adding up the coefficients of the second order IIR filter the sum is also = 1. Spare me the Math but is ...


IIR Filter Recommendations

Started by davidross in comp.dsp14 years ago 10 replies

Hi Folks, This is my first post on the list. Pleased to meet you all :-) This seems to be an excellent resource of DSP knowledge and I look...

Hi Folks, This is my first post on the list. Pleased to meet you all :-) This seems to be an excellent resource of DSP knowledge and I look forward to learning a lot. My first question is with regards to IIR filters. I am looking to design some IIR filters for audio (Low pass, band pass, and high pass). I know there are several design approaches available and several structures but i am inte...


Fixed IIR Filter Quality

Started by m2francis in comp.dsp14 years ago 7 replies

I have implemented a fixed point IIR filter and now comparing it against double precision implementation in simulink. I dont want to just...

I have implemented a fixed point IIR filter and now comparing it against double precision implementation in simulink. I dont want to just select 32 bits. I just want to have enough precision bits so thats its not unstable. What parameter do I use in order to measure the quality of the fixed point implemention? Is it the RMS on the difference between the two implementations? Mike Thi...


Question: linear predictive coding, spectral estimation

Started by Lars Hansen in comp.dsp14 years ago 4 replies

Hi I have a question about LPC-analysis. I have a frame of 256 speech samples which I assume is the output of an IIR-filter and I do...

Hi I have a question about LPC-analysis. I have a frame of 256 speech samples which I assume is the output of an IIR-filter and I do LPC-analysis of the frame to obtain the coefficients of the IIR-filter. I want to do a comparison of the non-parametric power spectrum (by use of FFT) and the model-based power spectrum to see how well they fit, but I am not sure if I have done it right....


IIR filter problem

Started by DX in comp.dsp14 years ago 3 replies

Hi Thanks for your answers. This is the problem... I'm building a IIR filter using fixed point, (well the limits are -1 to 1), I've...

Hi Thanks for your answers. This is the problem... I'm building a IIR filter using fixed point, (well the limits are -1 to 1), I've calculated the coeffs for the filter but there are values that are out of range of -1 to 1, for instance 4.5, or 2.8 etc... and other values that are in range for the same filter, for example 0.5, 0.126, etc .... Well I can't represent this 2 kind o...


IIR Filter for Baseband comms

Started by Mas Bas in comp.dsp14 years ago 4 replies

Hi, My simulations show that having IIR low pass filter to simulate baseband model of a communication systems will introduce inter symbol...

Hi, My simulations show that having IIR low pass filter to simulate baseband model of a communication systems will introduce inter symbol interference (ISI). regardless the filter type (Butterworth, Cheby, Elliptic,...) all gives a significant ISI. The simulation shows it gives a significant BER degradation, it can be around 3 to 5 dB. Is that a realistic value compared to the real ...


How to compensate for the passband droop of a Sinc filter with an IIR filter?

Started by daniel zuo in comp.dsp14 years ago 27 replies

Hello, I'm now designing a IIR interpolation filter. The interpolation filter consists of a IIR lowpass filter stage and a Sinc filter...

Hello, I'm now designing a IIR interpolation filter. The interpolation filter consists of a IIR lowpass filter stage and a Sinc filter stage. I dont know how to compensate for the passband droop of the Sinc filter. Can you help me? Daniel This message was sent using the Comp.DSP web interface on www.DSPRelated.com


Taps

Started by Jake in comp.dsp14 years ago 30 replies

How many taps does an iir filter have? TIA.

How many taps does an iir filter have? TIA.


Hands on DSP books

Started by Christian_ in comp.dsp14 years ago 3 replies

Hi, are there any good books out there that actually explain how to implement DSP in C. In particular I am interested how to caluculated...

Hi, are there any good books out there that actually explain how to implement DSP in C. In particular I am interested how to caluculated FIR/IIR filter coeffiencents and window them in C.


Slightly OT: Christmas wishes from Lyons

Started by Rick Lyons in comp.dsp14 years ago 24 replies

Hi everyone, Here's wishin' all you guys a very Merry Christmas and a Happy New Year! Of course, these good wishes are also directed at...

Hi everyone, Here's wishin' all you guys a very Merry Christmas and a Happy New Year! Of course, these good wishes are also directed at any of you who do not celebrate Christmas such as: Muslims, Hindi, God-less Atheists, Buddhists, software engineers, Sikhs, Jews, IIR filter designers, Shinto, Democrats, Neo-Pagans, transsexual lesbians, U.S. Government Employees, Scientologis...


Lattice Ladder Filter Structures

Started by davidross in comp.dsp14 years ago 9 replies

Dear List, I'm looking to convert my second order Direct Form IIR filter structure over to an equivalent second order Lattice Ladder filter...

Dear List, I'm looking to convert my second order Direct Form IIR filter structure over to an equivalent second order Lattice Ladder filter structure. Does anyone know of a good reference or link which details how to implement such a beast? Thanks for any information. Best Regards, David Ross


inverse laplace transform

Started by Bhaskar Thiagarajan in comp.dsp14 years ago 8 replies

Hi all I'm working on trying to model a non-linear system (described by a second order differential eqn) into a discrete IIR filter. I guess...

Hi all I'm working on trying to model a non-linear system (described by a second order differential eqn) into a discrete IIR filter. I guess I'm trying to follow the impulse invariance IIR filter design method. In the laplace domain, the transfer function looks like this H(s) = a^2/(s+a)^2 I tried looking up laplace transform tables to find the time domain form for this and the closes...


Help to interpret impulse response of an fixed point IIR filter

Started by Marko in comp.dsp14 years ago 11 replies

I have done an impulse response of an IIR filter. The impulse response of the filter does not return to zero but stops at a level close to zero...

I have done an impulse response of an IIR filter. The impulse response of the filter does not return to zero but stops at a level close to zero (I think it?s because limitations in fraction bits). The filter is implemented in fixed point arithmetic?s. And when I make an FFT of the impulse response de 0 Hz gain is not 0 dB as I would like it to be. But when I run a step response I...


Is it possible to replace an FIR with an IIR filter?

Started by Oliver Faust in comp.dsp14 years ago 2 replies

Dear group, I'm new here. I subscribed to comp.dsp because I'm puzzled by a statement from Simon Haykin in his book: Adaptive Filter...

Dear group, I'm new here. I subscribed to comp.dsp because I'm puzzled by a statement from Simon Haykin in his book: Adaptive Filter Theory (fourth edition) In section 1.6 page 52 he describes the Wold decomposition. There he writes: "... A solution of particular interest is an all-zero filter that is minimum phase, which means that all the zeros of the polynomial B(z) lie inside the ...


IIR filters design methods?

Started by alixman984 in comp.dsp14 years ago 4 replies

Hello Guys; To be honest, I'm very new to DSP as whole, but because of what i am studying in university i need to know about different IIR...

Hello Guys; To be honest, I'm very new to DSP as whole, but because of what i am studying in university i need to know about different IIR filter design methods. Searched the net and I got next to nothing. I was wondering if anyone here, would mind to share a link or information about IIR design methods. I do appreciate your help. Ali


Using IIR Filter Library for different frequencies on TI eZdsp f2812

Started by vickykulkarni in comp.dsp14 years ago 5 replies

Hi In 1 of my projects i need to implement 2 filters on input data. The frequency at which the filter is tuned is decided by the input of a...

Hi In 1 of my projects i need to implement 2 filters on input data. The frequency at which the filter is tuned is decided by the input of a GPIO. for example lets say i have to implement 2 low pass filters that could have passband frequencies from (20,40,80,150,600 KHz etc). The Gpio input decides which 2 filters to implement. Can i implement this using the IIR TI C2000 filter library? Essentia...


Stereo audio and Equalizer

Started by snigdha in comp.dsp14 years ago 10 replies

Hi, I am doing my study on graphic and parametric equalizers. I read through some of the previous posts on this site and was really helpful....

Hi, I am doing my study on graphic and parametric equalizers. I read through some of the previous posts on this site and was really helpful. I have one small question though. When I am presented with a stereo audio signal, would it be advisable for me to process the two channels using two separate IIR filter bands? Or just assuming the data to be continuous, can I just use one filter? Th...