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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. ...

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...

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...

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...

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...

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...

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...

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 ...

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...

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 ...

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; ...

Symmetry of Butterworth gain

Greetings, I am exploring Butterworth filters on Matlab. I created the filter weights using: [b,a]=butter(8,[.6438 .9328]); Now, I want to plot the gain of the filter using the following code given below. I plotted the gain using plot(abs(H)). I do not see symmetry in the plot. My co-wor...

Re: Improving SNR or a better Goertzel?

Jerry, It's a 3 pole Butterworth. I can change components to reduce the cut- off frequency, if that would help. John ...

Re: Audio

tuurbo46@yahoo.co.uk wrote: > hel@40th.com wrote: > > > If you only have three bands, you likely won't > > be that interested in the mid. freqs. to waste > > one. Concentrate on bass (under 100 Hz), upper > > bass (around 250 Hz), and treble (over 8 kHz). > > > > t46 [14 Jan 2006 02:43:...

Re: PID controller with second derivative?

On Mar 15, 3:22 pm, "Scott L" wrote: > On Mar 15, 1:32 pm, Jerry Avins wrote: > > > > Is there any reason to include higher-order derivatives in PID-like > > > control systems? > > Yes. It helps to stabilize higher-order systems. > > Do you know of an example of a real-world...

Bandpass filter techniques

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 ...

Re: FIR filters

tuurbo46@yahoo.co.uk wrote: > 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...

Anti-Aliasing filter

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 ...

Re: digital integration algorithm

Steve, I would think that a RC low pass filter can be modeled as a first order Butterworth filter with the -3dB cutoff frequency fc = 1/ (2*pi*R*C). Also, some details on recursive filter implementation is available @ http://www.dspguide.com/CH19.PDF HTH, Krishna http://dsplog.blogspot...

Help me with bessel filter concepts

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 ...

Re: Filter design.

The amount of the distortion due to aliasing equals to the sum of power for all components higher then Fs/2. Indeed the speech spectrum envelope falls at about 12dB/oct at high frequencues. The amount of the high frq content in the clear voice is very low. So just the direct sampling at...

designing an arbitrary 10 tap IIR filter

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 si...

Simulating analog filter with FIR

Any techniques for obtaining a 'best fit' digital filter (1st choice FIR, 2nd choice IIR) for an analog filter. The analog filter specifications be from an equation (e.g. butterworth etc) or a set of measured frequency response values. This will allow me to simulate digitally an analog proce...