Questions tagged [bode]
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49 questions
1 vote
1 answer
74 views
Is my Bode plot right?
I have a current signal and the corresponding temperature signal in .mat format. The current is input and temperature is output.I am trying to get the Bode plot of it so that I can design a low-pass ...
- 11
1 vote
1 answer
114 views
$360^\circ$ Phase shift between Bode plots of two similar systems
I am trying to identify the characteristics of an FIR filter in an ideal case as a sanity check. I observe that there is no strange behaviour, but there is an unexplainable issue in the phase plot of ...
- 153
0 votes
1 answer
63 views
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
0 votes
1 answer
150 views
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 ...
- 1
1 vote
0 answers
26 views
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
0 answers
71 views
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
1 answer
99 views
Extracting Transfer function from Bode's gain plot
Let the figure of the Bode's Gain plot of a certain transfer function, estimate what could this transfer function be: Here is what I tried to do: since at $\omega = 0 , |G(j \omega)|_{db} = 20\log(K) ...
0 votes
0 answers
101 views
Bode plot phase shift equation when poles and zeros are not at the origin
Let $$H(s)=\frac{s^{n}}{s^{m}}$$ For $n \ne m$ the phase shift between output and input will be $\frac{\pi}{2}(n-m)$. For situations where the poles and zeros are not at the origin, I could find the ...
- 153
1 vote
1 answer
722 views
Why does the discrete bode plot look like the following and if possible explain the black vertical line at the end for an averaging filter
Why in the attached image for a simple 3 point moving average that has been converted into a TF (z domain) is there a wired dip? It seems that when I change the sampling time, the dip shifts to the ...
- 215
0 votes
2 answers
106 views
Can you plot an irrational transfer function on matlab?
For example if I have the following transfer function: $$H(s) = \frac{1}{\cosh(\sqrt{s/10})}$$ Can I do the bode plot it in matlab or do I need to rationalize it beforehand?
- 25
0 votes
1 answer
236 views
Bode Plot - Why we add dB value in some situations?
Question: Specify the straight -line approximation of the Bode magnitude plot: $$H(j\omega) = 0.04 \cdot \frac{jw+50}{jw+0.2}$$ I don't understand that in the plotting part we add 6dB for two ...
- 17
0 votes
2 answers
271 views
Why do I need to multiply the frequencies with a number, to get correct "shift" in the bode plot?
Assume that we got a sine wave function $$u(t) = A\sin(2\pi \omega(t)t)$$ Where the frequency $\omega(t)$ changes over time $t$ and $A$ is the amplitude. Assume that we apply that $u(t)$ signal onto a ...
- 417
2 votes
1 answer
133 views
How does the phase/gain margin method work?
We have the closed loop transfer function: $$T(s)=\frac{L(s)}{1+L(s)}$$ So as far as I understand we check along the $j\omega$-axis on the Bode plot whether $L(s)=-1$, cause that's when $T(s)$ has ...
- 21
1 vote
0 answers
107 views
How can to obtain the hughcut, lowcut and bode constant of a bandpass digital filter?
I need to create a bandpass filter amplifier in python; and determine the transfer function, graph the bode diagram, and print the highcut frequency, lowcut frequency, the bode constant and the ...
0 votes
0 answers
28 views
How can to obtain the transfer function of a bandpass digital filter? [duplicate]
I've been asked to: create a bandpass filter amplifier in python, determine the transfer function, graph the bode diagram, and print the highcut frequency, lowcut frequency, the bode constant and the ...