# Questions tagged [bode]

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### Connection between positive feedback at DC and real-axis right-half-plane pole(s)

(Context provided here, question summarized at the end.) Suppose I have an open-loop transfer function with two coincident left half plane poles like $$H(j\omega)=\frac{-H_0}{(1+j\omega RC)^2}$$ ...
• 349
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### Methods to determine stability of open-loop systems

Which methods can be used to analyze the stability of open-loop systems only, closed-loop systems only, and both of them? As far as I understand, you can determine the stability of open-loop and ...
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1 vote
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### truncating a system and plotting it on bode

Let system G(s) be: $$G(s)=\sum_{i=0}^{10}\frac{(-1)^i}{(2i+1)^2}\frac{\omega_i}{s^2+2\zeta_i \omega_i s+\omega_i ^2}$$ $$\omega_i=\frac{(2i+1)\pi}{T}\, T=1\, \zeta_i=0.2$$ Its impulse response is an ...
• 11
1 vote
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### Does calculating the phase margin when the phase is positive has any meaning?

I want to calculate the phase margin and the gain margin of my transfer function to have an idea about the system's stability. The transfer function is quite complicated since it contains an ...
1 vote
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1 vote
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### 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 ...
• 11
302 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 ...
• 533
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### 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 ...
• 211
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### 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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388 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 ...
• 306
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### 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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1 vote
3k 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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1 vote
119 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 ...
443 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 ...
• 191
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### 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: ...
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 ...
1 vote
3k 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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1 vote
3k 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 (...
• 113
1 vote
69 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 ...
• 111
1 vote
3k 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 ...
• 113
1 vote
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 ...