Electrical Engineering Stack Exchange
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Questions tagged [transfer-function]

Anything related to transfer functions, i.e. those complex-valued functions of a complex variable used to model mathematically the I/O relationship of linear time-invariant initially-at-rest system using Laplace transform.

Anything related to transfer functions, i.e. those complex-valued functions of a complex variable (typically named s, a.k.a. complex frequency) used to model the I/O relationship of linear time-invariant (LTI) initially-at-rest systems using Laplace transform.

Given an LTI analog system whose impulse response is \$h(t)\$, its transfer function is $$ H(s)=L[h(t)] $$ Where L indicates the Laplace transform. It turns out that the zero-state response \$y(t)\$ of the system to the input signal \$x(t)\$ can be easily obtained in the s-domain by the formula: $$ Y(s) = H(s) X(s) $$ where uppercase letters indicate the Laplace transform of the signals involved.

See also Wikipedia on transfer functions.

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Poles and Bode Plots

I have three questions that have been troubling me for a long while: We say that, in a Bode plot, there is a drop in gain of 20 dB per decade whenever a pole is encountered. But aren't poles defined as the values of \$s\$ which make the transfer…
Vishnudas Thaniel S
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Determine transfer function from circuit

I'm studying my first year of electrical engineering and I am stuck with understanding how to determine transfer functions from different circuits. As of right now I'm trying to determine \$\omega_1\$ and\$\ A\$ in the following transfer function.…
JHCJ
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Find the transfer function of the following circuit

I want to find the transfer function of the following circuit algebraically: First of all, we realize since we have ideal op amps, the voltages at node \$1\$ and \$2\$ are the same as well as the voltages at \$4\$ and \$5\$ and thus \$6\$. We also…
Tanamas
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Low entropy transfer function, output impedance

I am trying to understand and apply the concept of low entropy transfer functions as outlined by C.Basso and equally stated by a couple of people here. As an example, I wanted to work through an L-C 2nd order filter feeding a load simulate this…
Igloo
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What's wrong with my FET transfer function?

The following is from the book Design of Analog CMOS Integrated Circuit, page 207. Find the transfer function of the circuit in Fig. 6.47(a): Suppose the voltage at node A is \$V_x\$. with the use of KCL at node B, $$V_x g_{m1} + \frac{V_{out}}…
kile
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The relation between s and jω

Supposed I have a tansfer function: $$\frac{s+1}{s+2}$$ So the zero of the tansfer function is -1, while the pole is -2. When we want to know about the frequency characteristics of the transfer function, we just use "jω" to substitute the "s", then…
T L
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Variable Frequency-Response analysis (amplifier)

I'm trying to understand what the book "Basic Engineering Circuit Analysis" by Irwin is saying at the chapter of variable frequency... It's trying to amplify a signal from 50 Hz to 20000 Hz. Where it uses this circuit to do that: So the transfer…
FelipeMedLev
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Why is the frequency domain representation of an integrator 1/s?

I am taking a linear systems and signals course and we are currently looking at system transfer function realization. The textbook states the following, A transfer function \$H(s)\$ can be realized by using integrators or differentiators along…
Blargian
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Complex transfer function complex conjugate issue

Going through Wireless Communication Electronics from Robert Sobot and came across the following. It's repeated throughout the book so my initial thought that it could be an error doesn't seem likely. Where does the square root come…
Jonty
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Are systems with more zeroes than poles really non-realizable?

I have learnt that systems whose transfer functions have more zeroes than poles become non-causal and thus non-realizable in practice for real time implementation. But an op-amp differentiator, like the one in the figure below, is certainly…
First User
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Determine Transfer Function from Step Response with Non-Zero Initial Condition

I saw in this forum a way to determine a transfer function from a step graph. I wanted to know how it is done when the initial condition is non-zero, like the following step response below. How can I estimate the transfer function of the system…
Surge_Arrester
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Why the output voltage of a transfer function is not equal to zero when the exciting signal is at the frequency of the zero

I was reading this document and I found something that I did not understand ... https://cbasso.pagesperso-orange.fr/Downloads/PPTs/Chris%20Basso%20APEC%20seminar%202016.pdf Suppose the following transfer function : $$\frac{Vout(s)}{Vin(s)} =…
Jess
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Understanding \$ j \omega \$ axis in transfer function

I understand the transfer function up to the point of \$ H(\omega) = \lvert H(\omega) \rvert \angle H(\omega) \$ where the magnitude and phase are decoupled into two separate functions, equivalent of saying \$ H(\omega) = { Y_0 \over X_0} \cdot…
KMC
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Difference between (s-Omega) and (1+s/omega) transfer function representation

In my lecture notes the transfer functions are represented as: $$ T(s) = k \frac{1+s/\omega_z}{1+s/\omega_p} $$ Where $$ \omega_{z,p} $$ represent the zeroes and the poles, respectively. What's the difference and how do I convert this format to the…
WantsToKnow
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How to find transfer function from a graph

I need help to find the transfer function of the system from this input/output graph:
anie
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