Questions tagged [bode]

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1answer
35 views

Stabilizing an unstable system and removing oscillations from step response

I have a system with the transfer function given in this MATLAB code ...
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2answers
48 views

How to deal with “weird” phase plots in bode diagram when designing a controller

I am trying to design a balance controller for a robot. With MATLAB simulink I arrived at the transfer function between the input and the pitch angle for the robot. I have plotted the bode and Nyquist ...
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1answer
60 views

Creating Bode Plot from Experimental Data

I have a blackbox system in which I can input a function and obtain the output signal (in MATLAB). I'm attempting to reconstruct a Bode diagram and have had success with the Magnitude plot, however, I'...
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2answers
171 views

Which step response matches the system transfer function

A system has the following open loop bode plot: - Which one of the plots below describe the closed loop step response for the entire system? My attempt My initial thought was to look at the static ...
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0answers
64 views

System identification from Bode plot

Please can anyone address me to routines (possibly for MATLAB/Octave) to identify system poles and zeros from its Bode plot (magnitude+phase)? I am aware there are functions for system identification ...
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0answers
21 views

Interpreting Nyquist Plot for Phase and Gain Margins

I have an open-loop system transfer function given by $G(s) = \frac{K(ABs^2+As+1)(Cs+1)}{s^2A(s(C+D)+1)}$ so I'd expect two poles at the origin and one at $s=\frac{-1}{C+D}$. After using Matlab to ...
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1answer
42 views

What is the frequency of the Gaussian white noise model in control systems?

The design of control systems, particularly for SISO systems, is made convenient by tools such as Bode plots and the corresponding Nyquist stability criterion. These concepts allow engineers to design ...
0
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1answer
327 views

Bode plot from from step response data

For quality control, I want to measure the frequency response of hardware I built. What I can easily generate on the hardware is a step response. Thus, I want to derive the magnitude and phase from ...
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1answer
35 views

Why is my MATLAB's bode plot wildly off?

I will give out all the details in case it is relevant. I have a MIMO state space system. I find its bode plot using MATLAB and separately using Mathematica. The plot from MATLAB is wildly off ...
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1answer
123 views

Analyze stability of a closed loop system with Bode

How can one know, with just looking at the Bode plots, if the closed-loop system is going to be stable or not? This closed-loop system is unstable, why? @DSP Novice @Jake It was my fault that the ...
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1answer
39 views

Why if I place the zero of the lead compensator at lower frequencies, do I obtain a resonance peak?

I am studying control systems, and I am studying the lead and lag compensator. I have seen than if I use a lead compensator for the closed loop transfer function, $T(s)=\frac{s+2}{(s+1)(s+8)},$ with ...
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2answers
84 views

bode plot, zero at 0Hz

I'm learning to draw magnitude bode plots from transfer functions: $$ H(s) = \frac{sRC}{sRC+1} $$ So I can see that I have a zero at s = 0, which corresponds to 0 Hz. I know this will add a +20dB/...
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1answer
74 views

Find the error in phase angle and dB gain Function Transfer

This is a question paper that I've tried to solved but seems I am missing something. My attempt: $$ |G|_{w=0} = K$$ So, $\require{cancel}|G|_{w=0.5a} = \dfrac{K}{\left|1+\dfrac{j0.5\cdot \cancel{a}...
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2answers
113 views

Matlab - Bode plot of Lag Filter + Integrator

I am rather new to Matlab and I just cant make sense of what I see in the bode plot of the continuous and discrete version of the same function. The bode plot of the continuous function looks as ...
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1answer
116 views

How to draw the magnitude plot of a variable slope low/high pass shelving filter? (eg. as a function of cascaded shelving filters)

I am interested in making a magnitude graph of a variable slope low/high pass filter. I would like to set slope in dB/oct and a cutoff pitch. The y-axis should be amplitude from 0 to 1, and the x-axis ...
2
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1answer
811 views

How do bode plots work with unstable systems work?

If I had a system with right-half s-plane poles, how would a frequency response work? Since a purely imaginary value for s, would cause the Laplace transform to diverge for such a system, what meaning ...
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1answer
955 views

Is there a way to obtain the transfer function from a bode plot on Python? (I know that it is possible on Matlab)

Quite simply, I have a bode plot obtained from a source signal. Now I wish to obtain the transfer function. I know it is possible with Matlab: http://www.mathworks.com/help/ident/examples/frequency-...
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2answers
294 views

How to make bode plot when output signal changes amplitude?

When I do frequency analysis on my feedback controlled system and the controller is really tightly tuned, I get a frequency response that looks like this: Blue is excitation signal and green is ...
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0answers
352 views

rank-1 array error using bode function

Some time a go i got a matlab script for speaker design. But since i don't use matlab i try to edit to python. Now i have a problem with the script. Since it is in the bode i was doubting which place ...
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2answers
2k views

Could someone please explain how to get frequency response of a given Bode Plot?

Having trouble with bode plots. I understand that the is to be converted to $dB$ but after that I'm stuck. Could someone please show me how this graph gives a frequency response of $10/1+jw10$
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0answers
56 views

How can I find the transfer function from this Bode diagram?

I've been given this bode diagram : I've been asked to find the transfer function only by using the bode diagram. It's the first time I'm doing this so here's what I thought. The starting value is ...
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1answer
365 views

What is the frequency response function for the Bode Plot pictured here?

I've forgotten how to get the frequency response function out of a Bode Plot. The phase component of $H(j\omega) = e^{j\pi/2}$, right? But I am having trouble finding $|H(j\omega)|$. How would I get ...
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1answer
255 views

Derive Bode Diagram from difference equation

I have designed a 2nd order low pass butterworth filter for the following: Sampling Frequency: 10kHz. Cut-off Frequency: 1kHz After doing a bit of maths I worked out the difference equation: ...
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1answer
2k views

Matlab freqz and custom implementation differences

I am making some homemade tools on Matlab. I made function that plot the frequency response of a discrete transfer function (just like freqz does). When I compare ...
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1answer
1k views

Slow and fast filter

According to my knowledge a filter with low cut off frequency is called slow and with hgih cut off frequency is called fast filter. I am trying to understand more about these two. I know what happens ...
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1answer
2k views

Bode plot of discrete-time transfer function $H(z)$

$H(z)$ is the transfer function of a biquad filter as described here. I would like to plot the Bode plot of the magnitude response of $H(z)$. Scipy has a bode method (...
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0answers
58 views

amplitude at exact frequency in wide band signal

Could anyone suggest the most computationaly efficient method for finding amplitude of exact frequency having a noisy wide band signal. To be more specific about a task. I have some physical ...
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1answer
1k views

Phase wrapping in Bode plot

I'm trying to model the transfer function of a linear system (a MOEMS mirror) based on a datasheet plot of its response. I'm developing the model in the python-control model and I think that I've got ...
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4answers
14k views

Analyze stability of a closed-loop system with Bode

I have an open-loop system function $L(s)$ and its Bode plot is As MATLAB says, it is stable if we close the loop with unitary feedback. I thought that, seeing the Bode plots one could tell if the ...