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help needed for Butterworth crossover response

Hi all, I implemented a butterworth crossover with the matlab (code given below). The code is working perfectly for a 4th order butterworth crossover(i.e. 24 dB/Octave). Th added response for the lowpass and high pass filters of the butterworth crossover gives 3 dB increase at the corner freq...

Who are Butterworth filters named after ?

Hi, I'm trying to dig some more info about Butterworth guy, that certaing group of IIR filters are named after. There are a lot of Butterworths in the history, so I'm curious which one is right... Thanks in advance, regards, Robert. ...

Re: delay added by matlab butterworth filter

Dirk, I think it depends on how one construes "delay". A _real_ Butterworth filte= r (as distinguished from a digital approximation) exhibits a response as so= on as an input is applied. It may be small enough to go unnoticed, but it's= there. Was Rune splitting hairs? Jerry ...

EVRC/butterworth filter

Is there somewhere a free code of a EVRC coodec? Or at least a sample of the first 6th order Butterworth filter? Gerard ...

Help: Phase Delay of Butterworth Filters

Hi All, Hoping someone can help me out. I'm working with Butterworth Filters and have some great equations for calculating the coefficients as a function of cut-off frequency: http://www.planetanalog.com/showArticle.jhtml?articleID=12802683&pgno=3 However I need a function which gives me...

biquad over butter

Hi all. I am trying to understand what the benefit would be of having a biquad instead of a butterworth filter in analogue implementation. For example, if I assume that -more or less- i need 2 integrating capacitor per pole, then i need the same for both a 8th order butterworth or a 4th order biqua...

Help with Butterworth Filter

Hi All, I've been plowing through pages of theory in dsp books trying to work out how to create a butterworth filter. They all seem to use different symbols and many different forms of the same equation. Lots of theory but very little of practical examples. Basically I have a series of 15...

Butterworth delay

Increases in analog filter order for a Butterworth filter increases its delay, correct? I've heard of methods for making up for the delay incurred - sometimes referred to as running the filter both backwards and forwards. Can anyone with practical experience in this domain shed some light on the...

Sigma-Delta Modulation into Butterworth Filter versus Ideal Lowpass Filter

I have been experimenting with a Butterworth filter. I must be making a mistake. Here is my problem. The impulse response of the first order Butterworth filter is a decaying one-sided exponential. Suppose that the filter is 1/(1 + j f/fc ). Then, the impulse response is 2 pi fc exp(-(2 pi...

butterworth high pass fourth order design

hi, can anybody help me to design and implement an fourth order butterworth high pass filter in s domain.here are the specs input = 1kHz sine order = 4 fs = 20kHz As = 80dB thanks in advance sid ...

variable gain in an Butterworth IIR

Hi, I'm not sure this has been hashed out before on comp.dsp, I searched the archives but no luck. so I'll ask: I'm designing a butterworth filter using the typical analog prototype, then converting it to LP/HP/BP/BS, then doing the bilinear transform then separating out the zeros/poles in...

Butterworth bandpass gain

Hi, I'm working on butterworth IIR filters, I have my s-plane analogue prototype and conversions to HP/BS/LP working fine and am able to calculate gain and scale it correctly, do bilinear and covert to SOS, no problem. I'm having trouble finding references about how to calculate an overall ga...

butterworth filter on pcb?

Hi: I've built a simple 2-pole low-pass Butterworth filter (maximally flat magnitude filter) with a cutoff frequency of 1kHz. I built it out of 741 op-amps and capacitors/resistors. What i want to know is this - can i buy a prefabricated filter like this that i can plug into a printed circ...

design a digital butterworth filter using matlab??

Dear members: In the demo in my class, my prof uses matlab to design a digital butterworth filter. He first designs an analog filter using funtion butter(, , 's') and then uses bilinear transformation to convert the analog filter to a digital filter. Since I know MATLAB function butter()allow...

Run time estimate of a butterworth filter

I am completely new to the field of DSP -- so this question may be elementry I was wondering about the worst case performance of a butterworth bandpass filter. I know that the FFT algorithm has a worst case performance of O(N log N). Does a second order bandpass filter have a similar computat...

bilinear transfermation

Hai! every one. This question is basic for DSP experts.I try to design digital butter worth filter(lowpass) in C.First I converted given digital specs to analog specs.after that i caluculated prewarped analog specs.I found order, cutoff frequency of analog butterworth filter.After that I used butte...

Scaling cutoff freq of Butterworth filter

Dear group, I am currently using a butterworth lowpass filter for filtering sets of parameter files. For this purpose, I found an "optimal" cutoff frequency to generate the filter. I have, however, the necessity of changing the "sampling rate" of the parameter set, but at the same time get t...

adding up coefficients

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 u...

Reg:Design of Butterworth approximated filter using FIR filter design technique

I need to design a butterworth approximated low pass, high pass, band pass, band stop filter characteristics.This i did using DFT technique which is a very heavy algorithm.So My question is how to design the FIR for my requirement.So can anybody help in how to proceed... Thank you :-) With...

Obtaining 1/3 octave levels from a PSD

hello i am looking for the easiest way to calculate 1/3 octave levels from an acquired signal sampled at a high rate (usually 350kHz). as i understand it, the usual method is to create a bunch of butterworth filters and calculate the RMS level in each band, decimating occasionally to incr...

Re: How to combine multiple biquad LP/HP stages to get 36db/oct and higher order filters?

Butterworth Filter Denominator Factors Order Quadratic Factors 1 s + 1.00000 2 s^2 + 1.41421s + 1.00000 (Q = 0.70711) 3 s^2 + 1.00000s + 1.00000 (Q = 1.00000) s + 1.00000 4 s^2 + 0.76536s + 1.00000 (Q = 1.30657) s^2 + 1.84776s + 1.00000 (Q = 0.54120) 6 s^2 + 0.51764s + 1.00000 ...

Bandpass IIR Filter design

Dear list Im designing a bandpass iir filter (prototyp) for a small realtime system. I already implemented the lowpass butterworth filter for a variable order by calculating the normalized butterworth polynomials in 2nd order systems and then applying the bilinear transformation. This res...

Re: IIR design

On May 15, 8:53 pm, "munib" wrote: > > I have to design a 6th order digital IIR bandpass filter, iam only given > passband edge frequencies and sampling freq.I do not have values for peak > passband ripple and minimum stopband attenuation and i can not use typical > values. sounds li...

Re: Which processor for decimation?

Any processor can do this. I would choose one that has a math library available as you may want to use floating point to make the implementation simple. You want a CIC filter followed by halfband compensation filter. Then your final butterworth filter. "Emiliano" wrote in message news...

Minimal lag, non-causal smoothing filter

I want to smooth time-series data with ideally zero-lag. The filter can be non-causal. I am currently using a butterworth filter and then advancing the output in time. However, since the butterworth filter's lag is not constant, the output series does not line up as desired with the input. My go...

General implementation of Butterworth filter questions

Having used up 5 days already, cutting and pasting the internet source code for Butterworth filters, only to have the audio spectrum analyzer show a terrible mess, I have to drop back to first principles in order to get something to work correctly. 1. I have the general Butterworth normalized pol...

Speech Recognition using Butterworth filters

I am aiming to build a very basic speech recognition system around an 8-bit microcontroller(PIC / AVR), which is capable of 'recognizing' four to eight words..(i.e, give a specific string output when it receives the corresponding input data through a mic.) Someone told me that designing Butter...

Roller Coaster Analysis

Hi everyone. I'm looking to see if anyone would be kind enough to help me out with a few basic questions I'm looking for answers for. Part of my job involves the analysis of the accelerations that are experienced by passengers on roller coasters. This involves fixing accelerometers to rides ...

IIR-Butterworth digital bandpass filter coeeficients

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 ...

delay added by matlab butterworth filter

Hi everyone, I searched around and couldnt quite find a problem like this, so sorry if there is a similar post already. In matlab I generate a simple 4th order butterworth filter, code below: [B,A]=butter(4,Wn,'low'); yf=filter(B,A,y); Where 0.0 < Wn < 1.0, with 1.0 correspondin...

Re: A question about bilinear xform and Butterworth LPF

John E. Hadstate wrote: > > Thanks, Robert. I had forgotten about the s--> 1/s > transformation. but that preserves the -3 dB corner frequency only in the normalized case. when W0 (the -3 dB corner frequency in the analog filter) is 1. in general to transform from an LPF to HPF, it's s/W...

Re: IIR band pass filter design query

On Aug 29, 8:03 am, "srikk123" wrote: > Hi, > > i have to design a digital Band pass filter using butter worth > 4th order filter.... the requirement is that the pass band frequency is > 1KHz and the sampling frequency is 48KHz. the filter should have a very > high Q factor...no b...

Wanted: critically-damped high-pass IIR filter

A critically-damped 2-pole Butterworth lowpass filter is described in http://people.umass.edu/exsci735/Robertson&Dowling.pdf A method to convert this filter to a highpass filter is described in http://www.health.uottawa.ca/biomech/lab/docs/ncb2_sm.pdf Those two papers are short and simple en...

zero lag Butterworth filter

Im trying to implement a zero-lag butterworth Filtert as described in tha paper at http://www3.uta.edu/faculty/ricard/Grad%20Biomech/Pezzack/Robertson%20(2003)%20Design%20and%20responses%20of%20butterworth%20filters.pdf My understanding is that the output of the filter needs to be reversed and...

Deriving the analog Butterworth filter from the maximal flatness condition

I've been wondering whether the often-stated maximal flatness conditions on analog Butterworth filters are enough to uniquely determine the coefficients of the transfer function? Let's review these conditions for a filter of order n: * The DC must be passed through the filter unmodified, |H(0)...

calculating the coefficients of a butterworth iir filter

Hallo everyone! I wanted to ask your advice on the following problem: i have to generate a butterworth iir bandpass filter with cutoff frequencies of 0.008 and 0.05 Hertz. This will be used in filtering a time signal sampled at 1 Hz (so the sampling frequency is high enough to work with the ti...

ButterWOrth filter using matlab

hi everybody, I am working on MAtlab for verification of Butterworth Filter for low pass filter, I have written the following program for it, N=20;%Order of Filter fc=200;%Cut-off frequency of filter fs=5000;%Sampling Frequency fin=1000;%Input frequency of pure sine wave ...

Re: group delay time?

Rune Allnor wrote: > On 5 Feb, 21:47, "alex65111" wrote: > > > As on level of pulsations group delay it is possible to estimate effective > > duration of the impulse response? > > I can't see that there is a relation between group delay > and the duration of the impulse response. ...

Is 'Bessel' digital lowpass filter standard?

Hi, I'm trying to design a simple IIR lowpass filter with the following specs: fs = 2.4kHz fc = 150Hz order = 3 or 4 The most important aspect is that the ringing (overshoot) shouldn't be higher than about 3%. When using a 3rd order Butterworth, I get about 9% overshoot, which is too much. ...

what is the roll-off factor and cutoff-slope of Butterworth filter?

Hi all, I am doing this in digital domain... I have used the Butterwork lowpass filter grabbed from Internet: % X and Y matrices with ranges normalised to +/- 0.5 x = (ones(rows,1) * [1:cols] - (fix(cols/2)+1))/cols; y = ([1:rows]' * ones(1,cols) - (fix(rows/2)+1))/rows; ...