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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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How can I extract elements from a transfer function matrix in Octave?

I am working with Octave in the control package, and I want to take an array of transfer functions (initialized as follows) and just extract the diagonal elements of the matrix. Whenever I try to do this, I run into the following error. I have tried…
Justin T
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Creating a MIMO (multiple input multiple output) transfer function system without hardcoding the number of inputs and outputs

Introduction As part of a larger system I'm trying to create a multiple input multiple output transfer function that only links inputs to outputs on the lead diagonal*. I.e. it has non zero transfer functions between input 1 and output 1, input 2…
Richard Tingle
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Wrong Nyquist plot using python control package

I am trying to use python to plot a Nyquist plot. However, I can't get it right. This is the code I am using: import control import matplotlib.pyplot as plt #Creating a transfer function G s = control.TransferFunction.s K0 = 10 T = 10 G = K0 /…
Sergio Polimante
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How to realize a transfer function with higher order of numerator than denominator in octave?

a=1 % Construct the trasfer function num=[a 1 3] den=[1 2 10] G=tf(num,den) % Impulse response impulse(G) % Step response step(G) When I click on 'run' this error appears "error: Order numerator >= order denominator"
Rebeca M
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Index of non-number element in Matlab

I have defined an array with transfer functions inside it. How can I find the position of a certain transfer function inside that array? s = tf('s') % defining a transfer function array = [s, s^2, s^3]; >> find(array==s) undefined function 'eq' for…
bergercookie
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transfer function in time domain

I have two signals in time domain (X and Y). I am trying to calculate the transfer function between them. I used the function tfestimate, which returns a transfer function as a function of frequency and a vector of frequencies at which tfestimate…
Jingfeng Li
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How to use eval in Matlab R2013a to replace a symbolic var s to the tf('s')

I created a multiple feedback second order lowpass filter that amplifies and also adds a dc reference to the output. To simulate it, I created the code below that used to work in a previous MATLAB version. Now in the 2013a version, it's not…
Prophet Daniel
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Matlab Adding two transfer functions

I'm trying to add two transfer functions together, for example: tf1=tf(1,[1 0]); tf2=tf(2,[1 0]); tsum=tf1+tf2 MATLAB considers tf1 and tf2 as blocks connected in series and therefore multiplies tf1 and tf2 together, the result is: tsum…
Sam
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How can I specify Time Delays in Linear Systems in Python?

this was asked 7 years ago in this thread: How to define LTI systems with Time delay in Scipy? The answer is outdated or at least I don't know how to make it work, and I would like to know if there is a way of doing this in the present. I want to…
Wonky
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Two versions of the same code return different results

I expect to get the same results when compressing these two MATLAB lines of code into one, but I don't! Code in 2 lines: [b,a]= butter(2,[0.4 0.6]) % Transfer function coefficients of the filter [A,B,C,D] = tf2ss(b,a) % State-space…
amansour
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PID controller and transfer function in C++

I have a PID controller working in simulink, but I want to pass it to C++ code. I found how to make a PID with code, something like this: error = input - refeed; iError += error * sampleTime; dError = (error - lastError)/ sampleTime; //PID…
Sik
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How to plot a transfer function from a Cauer network

The picture below shows a Cauer network, which is a continued fraction network. I have built the 3rd olrder transfer function 3rd Octave like this: function uebertragung=G(R1,Tau1,R2,Tau2,R3,Tau3) s= tf("s"); C1= Tau1/R1; C2= Tau2/R2; C3=…
BananaBowser
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How to give discrete input to a plant equation?

I have a plant equation.Say, Plant = tf([0 1] ,[1 1],'InputDelay',1); t = 1:1:100; Now I have a input value a= 0.0552 ,at the time instance t=1.I want to calculate output of the plant at t=1(which should be a numeric value as well!) How to do…
Sarit Hati
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How to separate the real and imaginary parts of a transfer function?

Here is a transfer function: S = [tf([10 2 4],[1 95 2000 3450])]; How can I get real(S) and Imag(S)?
Allen
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creating a digital filter in android

I'm trying to deal with ECG signal processing in android. I want to implement simple digital filters (lowpass, highpass) I've got a transfer function: here is what i've found: wikipedia - lowpass filter - it looks quite easy here. for i from 1 to…
user5094601
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