Questions tagged [bode-plot]

Anything related to Bode plots, i.e. a special graphical representation of the frequency response of a linear time-invariant system.

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Confused regarding gain margin and stability

I plotted the bode plots of the transfer function: G(s)= 2.123×10^6 ((0.105s+1.01))/(s^2 (s+12566.37) ) It is as follows: As can be seen, it shows the gain margin as negative infinity, however loop ...
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4th order low pass Butterworth filter with very low Q factor [closed]

I have designed a 4th order low-pass Butterworth filter with a 0.707 Q factor. However, what I am getting is almost no flatness in the pass band region and my frequency response looks like a half of a ...
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What will be the values of phase crossover frequency when the gain margin is infinity?

$$G(s) = \frac{s+1}{s^2+2s+100}$$ For the given transfer function I am getting the gain margin equal to infinity in the matlab, but i am not getting the value of phase crossover frequency. What will ...
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Butterworth Filter attenuates noticeably in pass-band

The Issue: I am using a Maxim MAX7480 8th order Butterworth low-pass filter to counter any aliasing from a sensor that measures signals up to 3kHz, but I only want up to 1kHz. Thus a critical ...
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Q: How to read this bode plot to find transfer function?

I am working on a blackbox system and I would like to make a Bode plot to find its transfer function. Since I do not have a lot of information on the system I am trying to input a series of sin waves ...
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About Negative Gain in Bode Plot regarding the Op-amp Circuit Design and its Relationship with the Feedback Resistor

I am new to the circuit simulation and now I am using Tina to simulate a op-amp circuit for a photodetector. I have some questions regarding the bode plot. Below is the circuit design, based on the ...
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What's the physical significance of a sinusoid's Bode magnitude?

What's the physical significance of a sinusoid's Bode plot's magnitude, at the sinusoid center frequency? Example: sin(wt), with w = 62.8 rad/s = 10 Hz. This has ...
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Why does a loop gain phase margin plot start from 180?

Bode plots are used to plot the the magnitude and phase of the loop gain - the mulitplication between the feedforward gain and the feedback factor, nothing else. Why do some plots start at -180 and ...
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Unstable system in s-plane but stable on bode plot?

I am reviewing bode plots and s-plane (pole-zero plots). I seem to have some confusion about them and how they relate to each other. I believe one is for closed-loop systems, the other is for open-...
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Frequency domain design of a PI controller for a first order system with transport delay

Let's say I have following first order system with transport delay $$G(s) = \frac{4563}{s + 64.77}\cdot e^{-0.000455\cdot s}$$ My goal is to design in the frequency domain a PI controller in the form $...
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Bode Phase Plot for negative transfer function

My question is relatively simple. Supposing that we have a transfer function of the type \$\frac{-Kj\omega}{\omega_0}\$. Then for the phase Bode plot, I should start from \$\pi\$ and then add \$\frac{\...
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How to recognize a non-minimum phase system from the Bode plot?

I have a bode diagram and I have to obtain if is it a non-minimum phase system or not. I think we could obtain zeros and poles from the Bode diagram but I'm looking for a fast way to find the answer. ...
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Using an oscilloscope to measure the gain of an op-amp circuit (with capacitors)

I have an upcoming laboratory exam where we have to construct an op-amp circuit (from our experiments the circuits were always varied and probably will be a bit more difficult on our exam.) We are ...
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Is it okay/valid to have a Bode plot that has linear magnitude scale?

I have almost always seen that the magnitude axis of a Bode plot is in dB but today I was shocked when I saw in LTspice that Linear option was also available for Bode representation. I am very ...
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Stability of the op-amp?

I am confused if the below amplifier will be stable or not when it acts as unity gain amplifier ( with a feedback factor of 1) ? My analysis: PM = zero from the bode plot , so the system is stable ! ...
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LTSpice: represent group delay when x axis changes

I am trying to plot the group delay of the following circuit. Usually it is enough to change the y axis from phase to group delay. However because I changed the x axis to represent a normalized ...
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Where is the origin pole in my CM buck SIMPLIS ac simulation?

I know that current mode buck regulators are generally stable as long as they're actually operating in current mode (i.e. the inductor ramp current is large enough to prevent slope compensation from ...
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How to verify the voltage and frequency response in a simulated equalizer?

I am working on a simple equalizer, intended to filter bass, midband and treble frequencies. I'm wiring the bode plotter of Multisim in a wrong way,perhaps. The circuit is: The idea is to measure the ...
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How to calculate the phase margin from Bode Plot if only the phase angle corresponds to the pole frequencies are given?

I have a Bode plot where only the phase angle corresponds to the two pole frequencies are given. The value of gain crossover frequency where the loop gain is unity is unknown. $$\mathrm{PM} = \phi - (-...
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Difference in Bode plot with table and Bode plot in Matlab

I am trying to generate a Bode plot for a transfer function of a high pass circuit. It's part of a solution to another question but this is the part that is confusing me. I have a transfer function: ...
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Why this overshoot in transient?

I am designing a forward converter whose output can be variable from 4V to 30V, 0-5A. This is going to be a pre-regulator for a linear converter. This is the schematic: I am using UC3844 controller ...
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Can any one explain what type of compensation is this

I will be using the UC3844 controller IC in combination with TL431 to achieve peak current mode control in a 150W forward converter. After some research, I found this schematic on the internet: There ...
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How to plot uncomensated loop gain in LTspice

I want to plot an uncompensated loop gain of a dcm flyback dc-dc converter. I know that I can derive the control to output transfer function and then plot the uncompensated loop gain but that just ...
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Visually determine pole from Bode plot

Currently I'm taking a basic electronics course and this was a part of homework. The Bode plot represents the frequency response of an amplifier and from this plot we had to determine the dominant ...
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Designing a bode diagram circuit

I have realized some low pass filters with a nominal cut off frequency around 10kHz, which I will use in combination with other filters to eliminate noise on DC and quasi-DC signals (around 30Hz). I ...
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Transfer function of an op amp with an Y or delta

What's the transfer function of the op-amp with a Delta from figure one? Such circuit can be easily converted into an Y, figure 2. Tina is calculating the transfer function from the Y circuit as H(s) =...
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How to find damping and the natural response in a system with a zero and complex pole pair

I want to know how to get damping and the natural response in a system with a zero and complex pole pair. I calculated the following transfer function: (from an active filter composed of 2 capacitors ...
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Identifying transfer function by its approximated graph

Consider the transfer function which is approximated graph is: I want to identify this function. As far as I can tell, since we see decreasing by \$-20db/dec \$ at \$10^{-1}\$, we can conclude that ...
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Is there a methodical way to desig multi-stage anti-aliasing filters?

Lately I've been thinking about the best approach to design multi-stage anti-aliasing filters in real-life. I know tools like Analog Filter Wizard or LTSpice can help to a certain extent, but they've ...
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Zero Order Hold Bode diagram

Here is the transfer function of the Zero Order Hold and its bode diagram: This transfer function is usually used for modelized a Digital to Analog Converter. Do you know why there is sharp roll off ...
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Why is the noise gain these opamps 500? I feel it should be 250

I wanted to check the bandwidth of the first stage of an instrumentation amplifier configuration and this is the circuit: Since, the noise gain of an opamp is (1+Rf/R1), for each of the op-amps the ...
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Is -3dB bandwidth defined for any type of transfer function?

If I have response like the following, is it still valid to say bandwidth of the circuit is 2.31kHz?
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Please help me clear up this confusion regarding gain margin and phase margin and unity feedback

I understand the physical significance of gain and phase margin. However, I would like some clarification regarding the mathematical aspects. Videos such as the following: https://www.youtube.com/...
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Preemphasis circuit, calculating H(s) and Bode plot

I have the following circuit: (which should represent a "new" design for preemphasis block in a FM transmitter circuit) I need to calculate the transfer function H(s) and draw a Bode plot. ...
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Phase lower than -180 when reaching unity gain, is it unstable or can we substract 360?

I am getting a phase of -434 degrees when reaching unity gain (0 dB point). The phase curve starts at 0 degrees, thus, can we consider that -434= -434+360= -74 degrees and the phase margin is of 180-...
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Bode Plot of Type 3 Compensator

I've designed a Type 3 compensator and wanted to see it's bode plot on matlab. Here is the transfer function of type 3 compensator: My values are: wp0=203 wp1=6657000 wp2=31400 wz1=5024 wz2=5024 The ...
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Which of the following methods tells Absolute stability & which method tells Relative Stability? Bode Plot, Routh Hurwitz, Root Locus, Nyquist PlotC

Which of the following methods tells Absolute stability & which method tells Relative Stability? I. Bode Plot ii. Routh Hurwitz iii. Root Locus iv. Nyquist Plot What i think is the following ...
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control system - is the gain positive or negative?

If the phase of a control system at high frequencies approaches to 0º then its gain K is negative. And if it approaches to -180º it gain is positive? Why is that? And how it works for low frequencies? ...
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How to find gain and phase margin from transfer function without Nyquist or Bode plot

Given transfer function L(s) as a ratio of polynomials of s, I know that we can find gain margin (GM) and phase margin (PM) by using a Nyquist or Bode plot. From a Nyquist plot: Find a point where ...
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flyback compensation design

This is the control stage circuit of flyback, I want to use SIMPLIS to measure the bode plot to prove a theory is matched to simulation, I use Mathcad to draw the bode plot, the SIMPLIS result should ...
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Finding resonant frequency or damping ratio from Bode Plot

I am working on a question where I have to estimate a transfer function from its bode plot. I plotted the asymptotes of this bode diagram, and was able to find out that this is 3rd order system with ...
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Plotting a Bode from a Transfer Function on Matlab

I need a bode plot for a transfer function from matlab which I never did before. I tried some examples but failed. How to do this on matlab? Here is the TF:
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How to prepare observation table and plot frequency response of Butterworth Sallen-Key High Pass Filter

My assignment: Design and simulate a Butterworth Sallen-Key High Pass Filter with the, fc = 10 kHz. Prepare the observation table and plot the frequency response. My answer so far: I want know how ...
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Bode plot starting from 180?

This is an NMOS common source amplifier and I'm trying to calculate the Phase Margin, but it's starting from 180 instead of zero? dose it mean I have poles at the origin or it's very stable?
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Remove big valley in phase plot

I am working on a speed controller for a robot and it's for when the robot is balancing on its wheels. I am designing the controller as part of a project in a linear control design course. However, ...
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I am miscalculating the Asymptotic Bode Plot

hope you are all doing well. Right now I am dealing with a homework and I have transfer function and I need to plot the asymptotic Bode Plots of it. I am trying to plot the Magnitude Diagram right now,...
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Is there an alternative to GCV (generator control voltage) to synchronize frequency sweep measurements?

A friend is taking a course in electronics engineering and asked me for help reproducing a lab experiment in frequency sweep measurement techniques. Students build a small RC filter and use a function ...
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Underlying reasoning behind lead and lag nomenclature of compensation

If \$0<z, \;p\$, the Laplace transform transfer function \$\frac{s+z}{s+p}\$ constitute two distinct types of compensators. If we look at this schematic, \$0<z<p\$ (lead compensation) implies ...
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How are the -3dB point and the pole of an op-amp related?

I have been looking at AC frequency responses for op-amps and I was wondering how an op-amp's pole and the frequency at the -3dB point are the same? They both mark the location where the gain starts ...
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unstable systems with positive phase/gain margin

Open loop Phase/Gain margins provide information on how much margin the closed loop system have until it becomes unstable. In other words, how much you can increase the effective loop gain and or ...
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