How to extract IIR coefficients w/Matlab?

Started by Mark in comp.dsp17 years ago 8 replies

Hello. 1. Is there an easy way in Matlab to take a z-domain transfer function and extract coefficients for an IIR filter type...

Hello. 1. Is there an easy way in Matlab to take a z-domain transfer function and extract coefficients for an IIR filter type implementation? I first designed my filter in the s-domain and tweaked it to get my desired response. I then used Matlab's c2dm with the Tustin method to get a z-domain transfer function. I am aware of "fdatool" but my filter started out life in s-domain and it...


improving sweep measurements (long)

Started by JR in comp.dsp17 years ago 1 reply

I measure a high Q resonance circuit with sweep generator. (transfer function re/im to be exact) There is a considerable delay until the output...

I measure a high Q resonance circuit with sweep generator. (transfer function re/im to be exact) There is a considerable delay until the output stabilizes. This makes the measurement quite slow. If I could use some multifrequency signal like MLS I would need only the time that impulse response decays to neglible level. Is there any way to improve sweep measurement speed or to get rid of...


CIC filters

Started by Robert Lacoste in comp.dsp17 years ago 7 replies

Dear dsp gurus, I have some difficulties to clearly understand how CIC filters should be implemented. Is there anywere a good introduction on...

Dear dsp gurus, I have some difficulties to clearly understand how CIC filters should be implemented. Is there anywere a good introduction on such filters, showing perhaps pseudo-code and transfer function as a function of the implementation parameters (number of stages, etc) ? Many thanks, Robert


Back to basic's

Started by Richard Owlett in comp.dsp17 years ago 6 replies

I think I've identified why some of my questions "do not make sense" and why some answers confuse me. While in school, some 40 years ago, I...

I think I've identified why some of my questions "do not make sense" and why some answers confuse me. While in school, some 40 years ago, I could write the transfer function of some simple RLC circuits almost by inspection. Yesterday I looked at ---R1----*----R2----* | | *----L1----* | | *----C1----* | ...


Is this statement correct?

Started by Randy Yates in comp.dsp17 years ago 30 replies

The system transfer function for an unstable discrete time system is given by H(z) = 0.8970 + 2.6911z-1 + 2.6911z-2 + 0.8970z-3 / (1.0 +...

The system transfer function for an unstable discrete time system is given by H(z) = 0.8970 + 2.6911z-1 + 2.6911z-2 + 0.8970z-3 / (1.0 + 2.3822z-1 + 3.0000z-2 + 0.7941z-3) H(z) is unstable because one or more of its poles is outside the unit circle. Note that nothing is mentioned regarding the region on convergence - assume it is free to be chosen. Also assume there are no restrictions...


cutoff frequency of a FIR Filter

Started by dnb in comp.dsp17 years ago 30 replies

Hi, I have learnt some amount of DSP recently by reading a few artickes (and using this newsgroup). I had a question regarding...

Hi, I have learnt some amount of DSP recently by reading a few artickes (and using this newsgroup). I had a question regarding cut-off frequency. Given an FIR Filter with Transfer function: H(z,N) = J . sigma_k={0...N-1} (z^{k-N}[k -1 ]) where J is a constant, is it possible to get a relation for the cutoff frequency in terms of N (in closed form)? In general, how does one determi...


Deriving the analog Butterworth filter from the maximal flatness condition

Started by Per Vognsen in comp.dsp17 years ago 6 replies

I've been wondering whether the often-stated maximal flatness conditions on analog Butterworth filters are enough to uniquely determine the...

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)| = 1. * The cut-off frequency must be at w = 1. (Cut-off normalization.) * The 2n-1 first derivat...


phase angle problems

Started by Steve in comp.dsp17 years ago 2 replies

Hi, I'm having some problems with phase angles, in the context of frequency response of a digital filter from its Z transform. I'm just not...

Hi, I'm having some problems with phase angles, in the context of frequency response of a digital filter from its Z transform. I'm just not "getting it". I've been looking around the 'web for relevant material, but all the stuff I've been finding is beyond this and just assumes that the reader can do this stuff. Say you've got a filter with transfer function: H(z) = z ------...


How to find stable transfer function?

Started by Bobby in comp.dsp17 years ago 11 replies

I have unstable transfer function H(z). One of the poles located outside of unit circle. I need to find stable transfer function G(z), which...

I have unstable transfer function H(z). One of the poles located outside of unit circle. I need to find stable transfer function G(z), which has the same Magnitude frquency response as H(z). Any ideas how can I do that? Thanks


Re: equivalence between Z-transform and Laplace-Transform

Started by Tim Wescott in comp.dsp17 years ago

AG wrote: > Hi Tim, -- snip -- > > > The term "damping ratio" is much more slippery when you're talking > > about discrete-time...

AG wrote: > Hi Tim, -- snip -- > > > The term "damping ratio" is much more slippery when you're talking > > about discrete-time systems. Assuming that I'm not messing up the > > math, if you find the pole locations of your transfer function, z_0 = > > e^{jw + q) then the "damping ratio" is > > > > zeta = q / sqrt(w^2 + q^2). > > What I finally discovered in reading books, is that


Question about IIR filter design using Impulse Invariance method

Started by Bobby in comp.dsp17 years ago 8 replies

I am designing low pass IIR filter using Impulse Invariance method. I've got transfer function H(z) which depends on impulse sample period...

I am designing low pass IIR filter using Impulse Invariance method. I've got transfer function H(z) which depends on impulse sample period T. I was asked to choose an appropriate impulse sample period T for H(z) such that the input signal x(t) = 5 cos(2pi(8000)t ? pi/3) ? 4 cos(2pi(40000)t + pi/2) sampled at a rate of Fs = 100 kHz has only the 8000 Hz sinusoid in the passband. I do...


Question about quantization

Started by Bobby in comp.dsp17 years ago 5 replies

I've got transfer function H(z) and determined location of poles and zeros. How can I recalculate location of poles and zeros using a...

I've got transfer function H(z) and determined location of poles and zeros. How can I recalculate location of poles and zeros using a minimum quantization level of 0.125 for direct form II, cascade, and parallel structures? Where can I find sample solutions for similar problems? Any online tutorial? Is there any Matlab function which solves this problem? Thanks in advance.


Delta-Sigma Modulator Loop Filter analytical equation not useful?

Started by Vincent Ma in comp.dsp17 years ago 14 replies

Dear friends, I am encountering a confusion in Delta-Sigma Modulator. Most of the references use a linearized model to model the DSM, and an...

Dear friends, I am encountering a confusion in Delta-Sigma Modulator. Most of the references use a linearized model to model the DSM, and an analytical transfer function can be derived. Refer to Shenoi's "Digital Signal Processing in Telecommunications", page 492, the denomenator of the transfer function for a second loop DSM is derived like z^2-z+alpha, where alpha is a parameter (alpha t...


Simple z-transform question

Started by ?ine Canby in comp.dsp16 years ago 3 replies

Hi, The transfer function for a lossy integrater is H(z) = z/(z-c) the magnitude spectrum is given by M(f) = |z|/|z-c| so lets...

Hi, The transfer function for a lossy integrater is H(z) = z/(z-c) the magnitude spectrum is given by M(f) = |z|/|z-c| so lets say I have a c value of 0.8, how do I plot M(f)? I simply tried plugging in values for z ni the range of 0 to 1, but this does not give me what I would expect and I think I'm totally misunderstanding the z transorm. Any help?


proving LTI System

Started by kjsudhir in comp.dsp16 years ago 4 replies

Hi, I would like to know how I can prove that the transfer function is an LTI system. with regards sudhir This message was sent using...

Hi, I would like to know how I can prove that the transfer function is an LTI system. with regards sudhir This message was sent using the Comp.DSP web interface on www.DSPRelated.com


LTI system and Non LTI system

Started by Abdul in comp.dsp16 years ago 13 replies

Hi, Let X(n)-----> Input Discreate Time Sequnece. H(n)-----> Impulse response of the system. Y(n)-----> Output Discreate time...

Hi, Let X(n)-----> Input Discreate Time Sequnece. H(n)-----> Impulse response of the system. Y(n)-----> Output Discreate time Sequnece. X(Z), Y(Z) are the z trasfroms of Input & output Discreate time sequnece and H(Z) is the transfer function of the system. Then the mathamatical relation ship holds Y(n) = X(n)(+)H(n) // Convolution Operation. Y(Z) = X(Z)*Y(Z) // Mult


From s space to time response with FFT

Started by Atmapuri in comp.dsp16 years ago 2 replies

Hi! I am looking for a method that can take an s domain transfer function and use FFT/IFFT to obtain the discrete time domain impulse...

Hi! I am looking for a method that can take an s domain transfer function and use FFT/IFFT to obtain the discrete time domain impulse response. Are there any aproximations that allow that? Thanks! Atmapuri.


Frequency response function...

Started by Atmapuri in comp.dsp16 years ago 2 replies

Hi! I have an s domain transfer function H(s) and trying to determine the response of the system to the unit step function. I tried...

Hi! I have an s domain transfer function H(s) and trying to determine the response of the system to the unit step function. I tried this: Y(s) = H(s) * X(s) = H(s) * Hc(s) = H(s)/s (* is product, not convolution) But the frequency response using freqs(Y(s)) is wrong. (I bet it must be obvious to someone why). The frequency spectrum should a have a value at DC (omega*j = 0) but ...


what are coefficients of a filter??

Started by Anonymous in comp.dsp16 years ago 4 replies

Dear folks I am studying about dsp and i need to calculate coefficients of a filter. I know that a filter is described by its transfer...

Dear folks I am studying about dsp and i need to calculate coefficients of a filter. I know that a filter is described by its transfer function H(w)=sum h(n)exp{-jwt). But I don't know what are coefficents of that filter. More specifically I need to present the coefficients of a filter g by the coefficients of a filter h, provided G(w)=exp(-wj)H(w+pi) Can I find the coefficients of...


Parametric description of Transfter function for 4th order Bessel filter

Started by Anonymous in comp.dsp16 years ago 5 replies

Hi, Does anyone know of a parameteric description for the transfer function (in Laplace domain) of a 4th order Bessel Thompson LPF, in terms...

Hi, Does anyone know of a parameteric description for the transfer function (in Laplace domain) of a 4th order Bessel Thompson LPF, in terms of its 3dB bandwidth? If not, is there an empirical way to scale the filter coeffs to get a specific 3dB cut off point? Thanks, Venugopal