## Forums Search for: Butterworth

## Which processor for decimation?

inHi, 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.

## biquad for resonant lowpass

inHi 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

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

inSome 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

## multi-band equalizer

inFor 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...

## low frequency IIR BPF - help !!

inHi All, I have never worked on DSP before so please forgive my lack of education! I have a signal sampled every 1mS by a 14bit ADC. From...

Hi All, I have never worked on DSP before so please forgive my lack of education! I have a signal sampled every 1mS by a 14bit ADC. From this signal I wish to extract a signal between 0.4Hz and 2.5Hz (while discarding some components less than 0.4Hz), so I designed a 2nd order butterworth BPF using Matlab, and it works fine. Next I implemented the filter on Visual studio using C#, and it wor...

## Phase delay VS frecuency for IIR Butterworth

inHi 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 ...

## DSP.SE and comp.dsp cross-over

inHi Guys, Just thought I'd post this...

Hi Guys, Just thought I'd post this link: http://dsp.stackexchange.com/questions/85/are-there-any-standard-implementation-forms-for-tunabl e-butterworth-filters to show that there's already some cross-over between comp.dsp discussions and DSP.SE content. Good to see! Ciao, Peter K.

## designing an arbitrary 10 tap IIR filter

inHi, i would like to design a 10 tap IIR butterworth filter with a given cutoff. What tools are available to help me realise this in C. for...

Hi, i would like to design a 10 tap IIR butterworth filter with a given cutoff. What tools are available to help me realise this in C. for example for RBJ's biquad filters there are equations on how to update your coefficients when your cutoff or sr changes. i'm looking to do something similar but on a higher order filter. thanks for any suggestions or pointers ... regards, sam ...

## Anti-Aliasing filter

inIf 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

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

inHello, 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...

## Help

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.

## Design of a Filter

Hi, I am modelling the physical layer of an 802.11 transmitter (to implement it into an FPGA). At this moment I want to design the...

Hi, I am modelling the physical layer of an 802.11 transmitter (to implement it into an FPGA). At this moment I want to design the digital filter responsible of pulse shaping (before the DAC). My doubts are: 1. FIR or IIR filter?, why?. 2. For each option (FIR or IIR) there are different types of filters (FIR: Raised_cos_Barlett, Raised_cos_Blackmann, etc, ... or IIR: Butterworth, Cheby...

## About Butterworth IIR filter ^_^

inHello 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...

## IIR filter design libray

inHi, 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 compute the response to a filter ?

inHello 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 ...

## IIR-Butterworth digital bandpass filter coeeficients

inHi 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...

## FIR filters

inHi all Im currently trying to design a FIR filter in Matlab (fdatool) v7.04 and im experiencing a few problems. A list of these have been...

Hi all Im currently trying to design a FIR filter in Matlab (fdatool) v7.04 and im experiencing a few problems. A list of these have been included below: 1) Im currently trying to design a filter with a flat passband and therefore i have choosen to use a butterworth - filter slope 12dB/ Oct. However when trying to select this option, Matlab blocks you. Is the reason for this FIR filt...

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

inI 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...

## Filter design pls help

inI was given a project to design, simulate and synthesize a digital low pass filter with cutoff frequency 150 Hz and stop band attenuation of 80...

I was given a project to design, simulate and synthesize a digital low pass filter with cutoff frequency 150 Hz and stop band attenuation of 80 db/decade The filter i have chosen is iir Butterworth filter with order 4 I have relialized the filter using fdatool in matlab Can any one pls help me with the vhdl code thx in advance