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Questions tagged [transfer-function]

A transfer function is a mathematical description of a system or part of a system. It relates the output of the system to the input. The system described by a transfer function is always linear and time invariant.

A transfer function is a mathematical description of a system or part of a system. It relates the output of the system to the input. The system described by a transfer function is always linear and time invariant.

Transfer functions are appropriate for single input single output systems; while several can be used to model a multiple input multiple output system it is usually more appropriate to use a state space representation in that case.

Common uses of transfer functions are;

  • Single-input single-output filters
  • Modelling systems for control theory
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Test if 2 transfer functions are the same in Matlab

Suppose that I have two transfer functions (or two matrices of transfer functions in the more general case). How do I test if these are the same (equal)? >> G1 = 1/(s*(s-1)); >> G2 = 1/(s*(s-1)); >> G1 == G2 % won't work..
bergercookie
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MATLAB: step responce of a system with complex data

I'm trying to have step response for a system with complex data. I have this error: "Cannot simulate the time response of LTI models with complex data." How can I have this response? this is my transfer function: (4.266-0.5157i) s^2 +…
fati
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ADC transfer function

I took over the project from someone who had gone a long time ago. I am now looking at ADC modules, but I don't get what the codes mean by. MCU: LM3S9B96 ADC: AD7609 ( 18bit/8 channel) Instrumentation Amp : INA114 Process: Reading volts(0 ~ +10v)…
Jin
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How can I find a transfer function between an input and output sampled at different rates?

I understand that normally I'd use ftest() after prepping my data with iddata(). However, for iddata() to work correctly I need to have both my input and output data be sampled at the same rate. Is there a rate-independent variant of iddata() or any…
Sanuuu
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How to implement a process regulator in C/C++?

The question is quite simple and I don't know where and how to implement the transfer functions. Let's say that I have a classic system where P has a transfer function of the second order with zita=0.7, F=1 and C is the process regulator. I would…
tzortzik
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Difference equation from transfer function, Matlab

I plotted the responses of two difference equation obtained from a Z transform transfer function. I used two methods and get two different results. Why? tf = y(output)/u(input) = z/ (z^2 - 3z + 3) Method 1, using Matlab, taking the inverse Z…
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transfer function with dead time

I have the following transfer function: (5/(s^2+1) ) * e^(-0.1*s) How do I include the dead time in the transfer function model? I tried A=tf([5],[1 0 1],'td',0.1) but doesn't work (td undefined).
Alexandru Severin
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Formatting A MATLAB Transfer Function (tf function)?

I want to input a transfer function for a PI controller in MATLAB (and eventually do a Nyquist plot of it), which has the general form: TF = [Kp + (Ki/s)] / [x + y + z ...] My question is, if I am using the tf() function to plot in MATLAB, how do I…
Rome_Leader
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Using System Identification Toolbox transfer function with Simulink

I believe I am doing something fundamentally wrong when trying to import and test a transfer function in Simulink which was created within the System Identification Toolbox (SIT). To give a simple example of what I am doing. I have an input which is…
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mathcad / matlab 3D plot of transfer function

I have a problem plotting a 3D plot of my transfer function. In matlab I have tryed this: [T,w] = meshgrid(1:1:32,1:1:100); sys2=20*log((1-w.*(T./2)./w.*T).*(((2.56.*(w.^2)+1.6.*w+1)./(0.0008.*(w.^6)+0.0124.*…
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Continuously updating transfer function

I have a transfer function that I am trying to use to filter acceleration data. So far I have been able to use lsim with a sin wave over about 10 seconds and I'm getting the result I expect. However, I cannot work how to get data to the function in…
Steve
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Matlab, configure output of TF (Transfer Functions)

When using the tf function in matlab, I'm not getting exactly the output I need. For example: tf( 1 , [1 1 1]) Produces: ans = 1 ----------- s^2 + s + 1 Continuous-time transfer function. What I desire is this: ans = 1/(s^2 + s…
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Is there an inverse for `tf()`?

I have the numerator and the denominator of a continuous time transfer function. I want to obtain the numerator and denominator of an equivalent discrete time transfer function separately. My code is as below: SAMPLING_PERIOD = 0.01; % Hc(s) =…
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Changing State Space Function mid Step response in Python

I am trying to change the used state space function for a step response and running into an issue. When it switches (at time 40s which for this example is just arbitrarily picked) I get a massive spike in position and velocity (10000x magnitude). I…
Hayden
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Is there a way to get the parameterised form of Transfer-Function/state-space representation of a RLC circuit in simulink?

I have a complex circuit at hand, and I want to find the state-space representation (or transfer function) of that MIMO circuit. I followed this article to generate the correct state-space representation for some specific value of resistors and…
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