Started by in comp.dsp12 years ago 1 reply

Hi all, Just found this piece of code from my old collection. But could not find where it came from? Can anyone shed some light? I know it is...

Hi all, Just found this piece of code from my old collection. But could not find where it came from? Can anyone shed some light? I know it is from butterworth and bilinear transform. But seemed not quite that, particularlly the resonanceDB to r part. ----------------------------------------------- c = 1.0 / (tan(pi * (fc / fs))); csq = c * c; r = 10.0^(-(resonancedB * 0.1)); q = sqrt(...

## Re: delay added by matlab butterworth filter

Started by in comp.dsp11 years ago

That's easy to know with a transversal filter. For a typical IIR, the transient decays exponentially and the time for it to fade out depends on...

That's easy to know with a transversal filter. For a typical IIR, the transient decays exponentially and the time for it to fade out depends on (among other conditions) the number of bits used. (You know that, but whitehat09 might not.) Jerry

## Bandpass filter techniques

Started by in comp.dsp17 years ago 11 replies

Some bandpass filters I have heard of: 1. Chebyshev 2. Butterworth 3. Raised Cosine What are the attribtues of theses filters that make...

Some bandpass filters I have heard of: 1. Chebyshev 2. Butterworth 3. Raised Cosine What are the attribtues of theses filters that make ones more useful than another in a given sitation? Iasac

## Which processor for decimation?

Started by in comp.dsp16 years ago 4 replies

Hi, i have to decimate my input data (16 bit resolution) from 10Khz to 10Hz using a 60db/dec or 80db/dec butterworth digital filter, i need to...

Hi, i have to decimate my input data (16 bit resolution) from 10Khz to 10Hz using a 60db/dec or 80db/dec butterworth digital filter, i need to know if this is possible using a standard MCU (for example 16 bit PIC) or is necessary to use a DSP core. Thanks in advance, Emiliano.

## Anti-Aliasing filter

Started by in comp.dsp14 years ago 12 replies

If you are estimating time-delay bewteen two microphones would it be better to use a Bessel filter for anti-aliasing rather than a Butterworth...

If you are estimating time-delay bewteen two microphones would it be better to use a Bessel filter for anti-aliasing rather than a Butterworth due to the approximate linear phase. Wang King

## multi-band equalizer

Started by in comp.dsp18 years ago 6 replies

For CD signals (sampling rate 44100Hz), Butterworth method is applied to design 10 bandpass filters. Center frequencies of these 10 bands are:...

For CD signals (sampling rate 44100Hz), Butterworth method is applied to design 10 bandpass filters. Center frequencies of these 10 bands are: 31, 63, 125, 250, 500, 1K, 2K, 4K, 8K, 16KHz, respectively. As weighting values (0.5, 0.5, 0.5, 0.8, 1.1, 1.3, 1.6, 1.6, 1.6, 1.6) are set to these corresponding 10 badns, the "Full Treble" style of music is achieved. It seems that the function of "Ful...

## Phase delay VS frecuency for IIR Butterworth

Started by in comp.dsp13 years ago 1 reply

Hi Everyone! I was hoping that someone could explain to me how I can calculate the phase delay of an IIR filter. I haven't found a way for doing...

Hi Everyone! I was hoping that someone could explain to me how I can calculate the phase delay of an IIR filter. I haven't found a way for doing it from H(z)... Or if it is not possible, which would be in your oppinion the smartest way to get it from H(s)? I have no code written for calculating poles and zeroes in my program and would like to avoid doing it if possible... Well, thank you very ...

## Help

Started by in comp.dsp12 years ago

I am seeking someone who would be willing to do contract work developing a simple 4th order butterworth filter application. This low...

I am seeking someone who would be willing to do contract work developing a simple 4th order butterworth filter application. This low frequency application simply needs to read in digital accelerometer 16 bit data via spi, filter, and send the data out to a PC. Like to use a PIC DSP. Need done asap.

## How to compute the response to a filter ?

Started by in comp.dsp13 years ago 6 replies

Hello all, well, it's been exactly 10 years since I last posted to this group, so my signal processing skills are rusty to say the...

Hello all, well, it's been exactly 10 years since I last posted to this group, so my signal processing skills are rusty to say the least. I've just implemented a basic IIR 2nd order low-pass butterworth filter in C and it's not working properly (coefs are correct). I know it's the very basics so I want to trace its response and compare it to standard responses I can find easily on the ...

## Help me with bessel filter concepts

Started by in comp.dsp15 years ago 6 replies

I am implementing a Crossover in c sharp platform. I have already implemented 24th order Butterworth and Linkwitz Riley filters. Now I need to...

I am implementing a Crossover in c sharp platform. I have already implemented 24th order Butterworth and Linkwitz Riley filters. Now I need to implement 24th order Bessel filter with cascaded biquad sections. Can any of you help me with the procedure? Regards Gangadhar

Started by in comp.dsp16 years ago 9 replies

Im trying to implement an 8th order Butterworth low pass filter in Matlab. I know you can design filters in matlab, but because of the...

Im trying to implement an 8th order Butterworth low pass filter in Matlab. I know you can design filters in matlab, but because of the specific implementation of my project, im doing with no matlab functions in an m file. So, the problem im having is that the input before filtering is EXACTLY the same as the output... what am I doing wrong? The sampling frecuency is 44100 hz. The filter cutoff...

## Why does low highpass in fir filter cause NaN?

Started by in comp.dsp15 years ago 2 replies

I am using a butterworth filter on a 1843200 point signal, sampled at 2048/second: n = 2; Wn = [lo hi]/(samplerate/2); ...

I am using a butterworth filter on a 1843200 point signal, sampled at 2048/second: n = 2; Wn = [lo hi]/(samplerate/2); [buttercoeffsB,buttercoeffsA] = butter(n,Wn); to bandpass a signal: filtereddata = filter(buttercoeffs(1,:),buttercoeffs(2,:),data); When lo and hi equal .2 and 80, or .3 and 60, the filtering works fine. But, if I try .2 and 60, or .3 and 80, only pa...

## IIR filter design libray

Started by in comp.dsp17 years ago 43 replies

Hi, I'm currently looking for a PC software library that can be used to dynamically design IIR filters such as Butterworth,...

Hi, I'm currently looking for a PC software library that can be used to dynamically design IIR filters such as Butterworth, Chebychev, Elliptic ... I can't find something that is very well kown. I'm astonished that there is no (or very few) popular libraries to face such a common problem. Does somebody know such a library ? The libray I'm looking for should : - provide routines able ...

## how to get rid of ringing with IIR notch filters?

Started by in comp.dsp18 years ago 20 replies

Hello, I have an IIR notch filter ( i.e. bandstop ), that rings like crazy whenever a transient signal comes through ... which is very...

Hello, I have an IIR notch filter ( i.e. bandstop ), that rings like crazy whenever a transient signal comes through ... which is very unwanted for my application. Anybody have any ideas how to get around this? I have to stick with IIR form filters. I've tried all the various standard design flavors, i.e. Butterworth, Bessel, Elliptic, etc ... but they all seem to ring unacceptably abou...

## About Butterworth IIR filter ^_^

Started by in comp.dsp13 years ago 11 replies

Hello Masters: When I develop a Butterwoth IIR filter. there is a strange phnomenon. After filter a standard sine signal with it, noise...

Hello Masters: When I develop a Butterwoth IIR filter. there is a strange phnomenon. After filter a standard sine signal with it, noise signal has been removed. but the amplitudes/peaks of each wave are not the same. for example, maybe one is 0.9994 and another is 0.977 etc. In fact, Some FIR filters also have this phenomenon. It confused me. Any remarks are appreciated an...

## Re: LPF butterworth filter question

Started by in comp.dsp10 years ago 78 replies

On 21 Mai, 08:59, zs wrote: > On m=E1j. 19, 19:37, Rune Allnor wrote: > > Again, you seem not to have the slightest clue what you > ...

On 21 Mai, 08:59, zs wrote: > On m=E1j. 19, 19:37, Rune Allnor wrote: > > Again, you seem not to have the slightest clue what you > > are talking about. > What I'm talking about is filter design and visualization: when > designing a filter, I think it's useful to see its actual response > first, without taking 'secondary' effects into a

## 50Hz bandstop filter don't work ....

Started by in comp.dsp10 years ago 12 replies

Hello Thanks to website: http://www-users.cs.york.ac.uk/~fisher/mkfilter/trad.html I have create a bandstop filter with this...

Hello Thanks to website: http://www-users.cs.york.ac.uk/~fisher/mkfilter/trad.html I have create a bandstop filter with this parameter: Parameter: ************************************************************************ filtertype = Butterworth passtype = Bandstop ripple = order = 3 samplerate = 500 corner1 = 48 corner2 = 52 *********************************************...

## IIR-Butterworth digital bandpass filter coeeficients

Started by in comp.dsp14 years ago 6 replies

Hi all... I'm new here. I found this list while searching the web for my problem. I'm an electronics engineer, and I have to design a filter...

Hi all... I'm new here. I found this list while searching the web for my problem. I'm an electronics engineer, and I have to design a filter for my project. In fact I haven't worked on DSP so much and I don't know so much about it. But finally I wrote a code for my filter, but there is something missing: COEFFICIENTS. I'm not good at calculating the coefficients, they were my nightmares at uni...

## Matlab filter coefficients

Started by in comp.dsp14 years ago 5 replies

Hi, I have a problem in designing a filter. I have a 4th order IIR Butterworth bandpass filter whose Second order systems are represented by...

Hi, I have a problem in designing a filter. I have a 4th order IIR Butterworth bandpass filter whose Second order systems are represented by : sos = [1 0 -1 1 -1.9837350041630541 0.98388232243107987; 1 0 -1 1 -1.7068352267865177 0.74814388078659311]; and the gain is: gain = 0.10073985362198344 ^ 2; I'm getting the filter coefficient values with sos2tf() function su...

## "Correcting" output of a filter

Started by in comp.dsp12 years ago 31 replies

"Correcting" is not going to be the right word, but here's my problem. I would like to have a brick wall filter with no phase delay...

"Correcting" is not going to be the right word, but here's my problem. I would like to have a brick wall filter with no phase delay and moderate computational complexity. (Yes, I know, who wouldn't). I'm actually using Butterworth lowpass filters of order 4 as designed by Tony Fisher's web page. Imagine I create a 4 pole LPF, with a corner frequency of 31Hz with a sampling rate of 44.1...