# 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.

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52 views

### Transfer function for CMOS opamp design

I am currently working on my bachelor thesis about readout interface for resistive gas sensors. In the whole schematic a use an opamp which I am currently trying to design. At first, I want to have ...
55 views

### 2nd Order Butterworth gain calculation at cut off frequency

The Butterworth 2nd order Low-pass filter has the following transfer function: $$\frac{\omega_c^2}{s^2+\sqrt2s\omega_c+\omega_c^2}$$ We know that at $s=\omega_c$, the filter attenuation is -3dB, but ...
42 views

### Does the law of reciprocity hold true for the phase response of an antenna?

I know that an antennas spectral transfer function should be the same in both transmit and receive due to the law of reciprocity, however does this law hold true for the phase response (AKA phase ...
51 views

### How can I calculate the parameters of an inverse Chebyshev active filter?

I'm currently designing an inverse Chebyshev 7th order low-pass filter with three 2nd-order low-pass notches and an RC low-pass filter. I've already used Simulink to obtain the s-domain transfer ...
45 views

### How can I find the transfer function with Laplace in the (s) domain?

How can I find the transfer function for this circuit with laplace in the (s) domain?
73 views

### Why don't these JFET simulations agree?

I was solving for poles and zeros of this JFET amplifier with an active load, and found an unexpected zero far off in the response when using the SPICE model. The large-signal and small-signal models ...
132 views

### Expression of a feedback circuit

I'm modelling a feedback circuit in Ltspice, however, I want to work out the transfer function for it. See below for the circuit. Now I want the form of Vfb/VOA_o as: So, I've thought about breaking ...
1 vote
373 views

### How do I find the transfer function of a PID that uses a single op-amp?

How does one go about finding the transfer function of the following op-amp PID? I have tried to convert each component of the circuit into it's transfer function representations, e.g., making each ...
265 views

### Transfer function help

I've been trying to model a circuit where I'm getting the gain of a non-inverting op amp connected to two probes. I've isolated the following feedback circuit and am trying to work out the transfer ...
87 views

### RC-filter transfer function confusion

simulate this circuit – Schematic created using CircuitLab I have a question about the transfer function of the above RC-lowpass filter. If I switch places of the capacitor and the resistor to ...
69 views

### How to explain this low-pass phenomenon?

I'm trying to understand how a coupling capacitor works, and build the following circuit. The transfer function (obtained from an AC simulation) from the voltage source (V2) to the gate voltage of the ...
81 views

### Derivation of the transfer function for an inverter-grid interface filter

I am reading a paper in which the filter interface between an inverter and grid is studied (figure 1) The paper started by giving the transfer function between the inverter's output voltage (Vbr) as ...
55 views

### Constructing Transfer Function (using voltage divider twice)

I have been trying to find the transfer function for this circuit, and I think I may have to use the voltage divider twice. What I have tried: I have used the voltage divider formula to find the ...
56 views

### How to get the transfer function for the diagram?

I want to obtain the transfer function for the current through the first resistor (i1)as i1(s)/vi(s). Could you help me with that?
70 views

### Question related to damping, quality factor and natural frequency of the system

If the G(S) is as follows: Then how would you calculate the value of undamped natural frequency, damping factor, and quality factor of the system?
1 vote
73 views

### I am wondering if magnets can be safely used to connect power from one to the other? [closed]

I am thinking of trying to create a extension cord that can be taken apart or separated as needed. And rejoined at any length of cord but connected only through magnetic connections. So I'm wondering ...
117 views

### Transfer function of the below circuit

How to find the transfer function of the below circuit? Please specify the steps, as i would like to learn. For anlysis, i consider V1 = 0 and all capacitor open. Thus, Req = 14.7k // 14.7k = 7.35k, ...
143 views

### Bode Plots and Transfer Function

How would you find generic form of this transfer function given these bode plots? I am having a hard time since the phase angle "dips" instead of going up.
107 views

### How to find transfer function for this pi-filter using FACTS Method with 6 reactive elements?

Am trying to apply the FACTS method to find out the transfer function for this circuit as shown below. This is a Pi-filter circuit with all its component parasitics and also including the source and ...
71 views

### Damping gets better, but overshoot increases. How can I explain it?

I have three transfer functions as below The pole-zero plot and the step response of the transfer functions are given as It makes sense to me that G3 has a better damping than G2 and G2 has a better ...
97 views

Given this circuit I’m asked to determine the transfer function from $V_i$ to $V_o$, but there are no answers given and my result disagrees with my earlier DC analysis. I think think the first “...
55 views

### What is the standard form for writing the second order transfer function for Input impedance?

When writing the transfer function for a system, the Characteristic equation in the denominator which carries information about the poles of the system is equated with the standard second order ...
183 views

### Assign Bode plots to Nyquist diagrams

How do I assign the following Bode plots to their corresponding Nyquist diagram? Can i tell the number of poles of the transfer function of the nyquist plot, by looking at w→infinity (from which of ...
1 vote
223 views

### Deriving a transfer function from Nyquist plot

I am given a half Nyquist plot and exercise as below I know how to plot a Nyquist curve for a given transfer function but I have trouble doing it the other way. I stumbled upon this post Deriving ...
106 views

### Construct a circuit to obtain the transfer characteristics

We were doing analog circuits lab for which our instructor asked us to construct a circuit from the transfer characteristics (I have attached the image.) We were working on RC integrators, ...
70 views

### Circuit design and frequency response of cascade PI controller

A controller system is built with tow cascaded PI sub-controllers like shown in the circuit below: I have design the circuit for simulation of PI controllers used in DC motor control.The first ...
92 views

### The center and radius of root locus

With this opened-loop transfer function, \begin{align*} L(s) & = \dfrac{K(s+2)}{s(s+1)} \end{align*} I would like to plot the root locus of this system. Based on the textbook,...
126 views

### Is there a way to take this buck diagram and reduce it to an AC transfer function?

I am semi-dangerous with switchers but I've never really delved into the innards of them so I'd like to ask about this TPS23750 diagram. I would like to develop a model of this feedback loop of a buck ...
230 views

### Negative phase margin and misconception of the point of instability in negative feedback control loops

Prelude Consider a canonical block diagram of a negative feedback loop with gain $K$, plant transfer function $G(s)$ and feedback transfer function $H(s)$: - Regardless of what functions K, G, ...
82 views

### Transfer function of buffer

Not really sure on how to proceed I got (Vin - Vout)/10K + (Vin - Vout)/wc = 0 I need to determine the poles and zeros for the same The motive is to understand the pole added by the capacitor at some ...
52 views

### Analysis of Op-Amp with Positive and Negative Feedback

I'm trying to understand the analysis of the following schematic: Specifically, the following line of logic Where the authors claim that the transfer function of the LC tank H(jw) is written with ...
1 vote
140 views

I am looking for the transfer function Vout / Vin of the following system, including loading. Could you help me find it? I have tried deriving the equation myself, but the derivation is too complex ...
1 vote
208 views

### How to find the Transfer Function of this circuit?

I am trying to find the transfer function of this circuit, but I can't find how. Does anyone have a clue?
1 vote
254 views

### Deriving transfer function from nyquist plot

I am given a half Nyquist plot as below The dashed line stands for the asymptote of the locus and the poles are 0 or negative at real parts, besides there is no double root in the transfer function. ...
50 views

### Calculate the Transfer Function of an AOP circuit

I am trying to calculate the transfer function of this circuit. Does anyone have an idea about it? Image source: Analog Devices - Circuit Note CN-0276 - part of Figure 2. Excitation Driver and Filter ...
1 vote
150 views

1 vote
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### Locating variables a and b in a phase lead compensation system

I have a block diagram that looks like this: I am asked to find the maximum angular frequency of the phase lead compensation, thus, in order to locate values a and b, I first find the maximum phase ...
124 views

### Finding K values for all poles of real parts are less than -2

I have an open loop transfer function with k > 0 as below: $$L(s) = \dfrac{k}{s(s^2+8s+25)}$$ Now for the closed loop transfer function, I would like to find the k value which makes all the ...
27 views

### How do you calculate output voltage noise for reactive circuits?

For circuits without any reactive elements, like voltage dividers for example, it's a relatively straightforward process to find what the output noise will be due to any present resistors. First, I ...
50 views

### What does the real axis of a transfer function mean?

Let's say I have a system that has a transfer function $H(s)$. Now $s = \sigma + j \omega$, so $H(s) = H(\sigma + j \omega)$. If I am not mistaken, the imaginary axis $j \omega$ ...
278 views

### RLC circuit transfer function

I'm trying to obtain the transfer function which relates the input voltage with the inductor's voltage H(s) = Vl(S)/U(s) so far I've tried to use Kirchoff's Laws in order to find it. Any suggestions? ...
231 views

### Finding transfer function from diagram

I'm trying to find transfer function of this block diagram. So far I've started with the smallest loop, but it's nonsense because don't know how to deal with Tf(s)(Friction torque) to Motor angular ...
33 views

### Barkhausen stability criterion and poles location in s domain

For studying stability, I am actually working with 2 methods : Here is the Barkhausen stability criterion : The loop gain is equal to unity in absolute magnitude, that is, $$|\beta A|= 1$$ and the ...
1 vote
99 views

### Transfer function of capacitor and resistor connected in series and one resistor connected in parallel with the capacitor

I have been trying to derive the transfer function H(s) of the circuit diagram. I know how to derive CR circuit, but I'm stock on connecting another resistor with the capacitor. Can anyone help me ...
75 views

### Why do I get two different transfer functions for the same gain?

I'm trying to derive the expression for $A_X = \frac{V_X}{V_{IN}}$ but I'm getting two different ones relatively to the $KCL$ I use to calculate it. With \\$ KCL \; A)\; -\frac{V_{IN}}{R_S} = \...
122 views

### Variable Reference point in control system

In some control systems that my be composed of cascaded control loops, the reference signal of an inner loop may come from the output of the outer loop. Example in DC motor control, we have an inner ...
1 vote
150 views

### Negative damping ratio for second order transfer function

For this circuit: We get this transfer function (this is the solution of another student, but I did it by hand and I get the same thing): Where the first damping ratio is negative. I read on another ...