## combine transfer functions

Started by in comp.dsp16 years ago 12 replies

I have a transfer function as follows: h(t) = p(t) - p(t - T) where t is time, T is some real value, and p is the impulse function, p...

I have a transfer function as follows: h(t) = p(t) - p(t - T) where t is time, T is some real value, and p is the impulse function, p = {1,0,0,0,...}. My question is, because T is a real value and not just an integer, how can i implement a matlab function to evaluate h for some arbitrary length? I can implement h making T an integer and I can get the impluse reponse of a fractional ...

## Multivariable control via Transfer Matrices?

Started by in comp.dsp15 years ago 2 replies

reading my old copy of 'Modern Control Engineering' by Ogata, 1970, (ok, no longer 'modern'), pg 117 describes a method of multivariable control...

reading my old copy of 'Modern Control Engineering' by Ogata, 1970, (ok, no longer 'modern'), pg 117 describes a method of multivariable control using a 'transfer matrix' of Laplace transfer functions where Gij(s) is the transfer function from ith input to jth output. Would this be practical to actually implement? Assuming I could model each Gij(s) as a simple 2nd order function, and only ...

## Transfer Function of Two Filters in Parallel

Started by in comp.dsp13 years ago 7 replies

I have two filters in parallel. The transfer functions are given by H1 and H2. I've illustrated the setup below. .-- H1 ---. ...

I have two filters in parallel. The transfer functions are given by H1 and H2. I've illustrated the setup below. .-- H1 ---. | | in --------| (+)------> out | | '-- H2 ---' How do I find the transfer function of two parallel filters? Do I merely sum the two together? sum = H1+H2 I would think this would w

## safe FFT resolution reduction and transfer functions

Started by in comp.dsp10 years ago 14 replies

Hi All, The context: I'm using Matlab to calculate a transfer function based on spectra measured with several data-acq systems. My...

Hi All, The context: I'm using Matlab to calculate a transfer function based on spectra measured with several data-acq systems. My problem is that the FFTs are "hi" resolution and because of the different setups, the resonant frequencies don't line up nicely. I suspect the resulting transfer function doesn't capture the true system. I'd like to reduce the resolution of the FFT...

## Interpolation of a complex transfer function.

Started by in comp.dsp16 years ago 1 reply

Hello all I have a complex transfer function e.g. like this: Y=[0.1+0.2i, 0.3+0.77i, 0.11+0.22i] corresponding to a frequency vector e.g....

Hello all I have a complex transfer function e.g. like this: Y=[0.1+0.2i, 0.3+0.77i, 0.11+0.22i] corresponding to a frequency vector e.g. X = [1, 3, 5] Now I want to have the frequencies between the points of my oryginal vector e.g. X1=[1.2, 2.5, 4.2, 4.8, 4.9] And I want to find a corresponding vector Y1 of complex values. The question is whether I can perform an interpolati...

## transfer function confusion and MATLAB

Started by in comp.dsp16 years ago 1 reply

hello - in this pdf paper http://www.telecom.tuc.gr/paperdb/eurospeech99/PAPERS/S11O2/K046.PDF the authors used a particular "pitch predictive"...

hello - in this pdf paper http://www.telecom.tuc.gr/paperdb/eurospeech99/PAPERS/S11O2/K046.PDF the authors used a particular "pitch predictive" filter to remove periodicities in an input signal. It is equation (2) of the paper, and is quite simple looking. I am having a few problems understanding it and how to implement it in matlab. The equation is: H(z) = 1 - (z ^ -P) F(z) where (...

## transfer function confusion and MATLAB

Started by in comp.dsp16 years ago 1 reply

hello - in this pdf paper http://www.telecom.tuc.gr/paperdb/eurospeech99/PAPERS/S11O2/K046.PDF the authors used a particular "pitch predictive"...

hello - in this pdf paper http://www.telecom.tuc.gr/paperdb/eurospeech99/PAPERS/S11O2/K046.PDF the authors used a particular "pitch predictive" filter to remove periodicities in an input signal. It is equation (2) of the paper, and is quite simple looking. I am having a few problems understanding how to implement it in matlab. The equation is: H(z) = 1 - (z ^ -P) F(z) where (z ^ -P) ...

## Reverberation Question

Started by in comp.dsp16 years ago 13 replies

Suppose I have a sound source and one microphone. I can assume that the transfer function on reaching the microphone is az^-5 (say) where...

Suppose I have a sound source and one microphone. I can assume that the transfer function on reaching the microphone is az^-5 (say) where z^-5 is a five step time-delay and 'a' is an attenuation factor

## Math versus signal processing; terminology differences?

Started by in comp.dsp16 years ago 9 replies

As a signal-processing person, I am trying to wade through some heavy-duty math papers and having a problem. Suppose that you have a...

As a signal-processing person, I am trying to wade through some heavy-duty math papers and having a problem. Suppose that you have a signal-processing network that is represented by a transfer function (either Laplace or Z, doesn't matter right now). Suppose that this transfer function is of the form; H(s) = a(s) + b(s) + c(s) ... to infinity Assume, for example, that a(s), b(s), etc, ...

## Delta Sigma ADC + channel switching

Started by in comp.dsp16 years ago 1 reply

Hi ! I have the following question: If I use an AD7738 (Analog Devices) or ADS1256 (TI) 24bit delta/sigma ADC with "fast channel switching" (I...

Hi ! I have the following question: If I use an AD7738 (Analog Devices) or ADS1256 (TI) 24bit delta/sigma ADC with "fast channel switching" (I think it's some mechanism to flush the digital filter so that you don't have to throw away 6+ samples before you get a valid one), what effect on the anti- aliasing filter requirements and transfer function does the channel switching have ? It wo...

## Minimum Phase Impulse Response

Started by in comp.dsp16 years ago 38 replies

Does anyone know how to find the precise minimum phase discrete-time impulse response corresponding to a given magnitude spectrum, when the...

Does anyone know how to find the precise minimum phase discrete-time impulse response corresponding to a given magnitude spectrum, when the magnitude spectrum does *not* correspond to rational polynomial transfer function?

## LMS identifying Non-Min Phase systems

Started by in comp.dsp16 years ago 8 replies

Suppose we have two signals - a Primary and Reference as in classical noise cancelling except that the mics are about one foot apart (for...

Suppose we have two signals - a Primary and Reference as in classical noise cancelling except that the mics are about one foot apart (for an acoustic problem). Let us suppose that the top path (for simplicity) has a transfer function (1-0.5z^-1) and the bottom path has a TF of unity. This of course is not realistic but I want to keep the sums easy. Now if we use LMS the LMS algorithm will c...

## Dtihering, gain and again...

Started by in comp.dsp16 years ago 12 replies

Hello, I was following the nice thread about dithering a signal in case of a gain (> 1) is applied. I've a couple of naive...

Hello, I was following the nice thread about dithering a signal in case of a gain (> 1) is applied. I've a couple of naive questions. Let's say the gain factor is 5.6, let's say there will be no clipping (target integer is big enough or input range in small enough). Now, the transfer function will be something like: 0, 1, 2, 3, 4, 5, 6, ... 0, 5.6, 11.2, 16.8, 22.

## IIR design and stability

Started by in comp.dsp11 years ago 10 replies

Hi all ! Thanks for reading ! I would like to design a 1st order digital high pass filter with a 50 us time constant. The analog transfer...

Hi all ! Thanks for reading ! I would like to design a 1st order digital high pass filter with a 50 us time constant. The analog transfer function is Ha(s)=50E-6*s/(1+50E-6*s). Then I use the bilinear transformation. Sampling freq is 48 kHz. The pre-warped pulsation is 0.4228 rad/sec and the z transfer function is H(z)=236.4E-6*(1-z^-1)/(1+0.999527*z^-1). When I compute this filter, i...

## J.17 s -> z conversion

Started by in comp.dsp16 years ago 8 replies

I am trying to implement J.17 de-emphasis cure in a 32 bit processor. I have converted J.17 S-domain transfer function using Bilinear of MATLAB....

I am trying to implement J.17 de-emphasis cure in a 32 bit processor. I have converted J.17 S-domain transfer function using Bilinear of MATLAB. The maltlab plot of manitude responce matches with the table biven in the std. But when i verify in Audio precession I get +5dB error in the range of 2-4 Khz. I have implemented in Directform 2 type filter. Does nay body has idea why i am getting thi...

## Super-resolution technique

Started by in comp.dsp16 years ago 3 replies

Hi! I have performed some propagation channel measurements in frequency domain i.e. I stored the measurement data as complex...

Hi! I have performed some propagation channel measurements in frequency domain i.e. I stored the measurement data as complex transfer function. I know I can obtain the channel impulse response by taking the IFFT. My question is, instead of taking IFFT. Can I employ other techniques (usually called super-resolution techniques in radar/wireless communications) such as ESPRIT, EM, SAGE, et...

## Symbolic Methods in Transfer Fct - Get Diff Eqn from Data

Started by in comp.dsp16 years ago 2 replies

Suppose I have data in and data out, so I do Fourier transforms and divide them to get the transfer function numerically and then invert...

Suppose I have data in and data out, so I do Fourier transforms and divide them to get the transfer function numerically and then invert back into time domain. But what I really want is given data, get the Difference Equation, as I would if I solved the system using Z-Transforms. I know this would be leading-edge, but given the advanced state of symbolic computation, I don't see why this...

## Laplace to Z transform for second order lag.

Started by in comp.dsp5 years ago 12 replies

I have a problem with verifying the results for the conversion of a Laplace transform to a z transform. The Laplace transform is in a table and...

I have a problem with verifying the results for the conversion of a Laplace transform to a z transform. The Laplace transform is in a table and is: (b-a)/((s+a)*(s+b)) The z transform for this transfer function is: ( z*(exp(-a*T)-exp(-b*T))/((z-exp(-a*T)*(z-exp(-b*T)) Now let: a=1 b=2 T=.001 Where a and b are the poles and T is the sample interval. When s-> 0 the Laplace transfer

## filter design for a bandpass noise shaper

Started by in comp.dsp15 years ago 2 replies

Is there a simple way to design noise-shaping filters using (for instance) the tools in the MATLAB Filter Design or Signal Processing libraries?...

Is there a simple way to design noise-shaping filters using (for instance) the tools in the MATLAB Filter Design or Signal Processing libraries? I would like to design a short FIR band-stop filter under the constaint that its zeroth-order (i.e. leading) coefficient is unity. This is because the noise transfer function has the general form: G(z) = 1 - z^-1 * H(z), where H(z) is causal. S...

## Basic IFFT Question - Please tell me if this is correct ...

Started by in comp.dsp15 years ago 4 replies

Hi, I have collected the complex transfer function H(f) of a device using a network analyzer. The data is between frequencies f1 and f2...

Hi, I have collected the complex transfer function H(f) of a device using a network analyzer. The data is between frequencies f1 and f2 and there are N available points (N is usually odd). I wish to use IFFT to study the time-domain response of the system. Now, my frequency resolution, fR = (f2 - f1)/(N-1). Hence, my sampling time would be tS = 1/(N*fR) which gives, tS = (N-1)/(N*(f2 - f...