Electrical Engineering Stack Exchange
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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.

Anything related to Bode plots, i.e. a special graphical representation of the frequency response of a linear time-invariant system, which is a complex-valued function of frequency describing how the systems reacts to sinusoidal signals of different frequency.

The frequency response \$H(f)\$ of a system is related to (and sometimes mistakenly confused with) its transfer function \$G(s)\$ by the formula:

$$ H(f) = G(j 2 \pi f) $$

Bode plots are the plots of the amplitude (in decibels) and phase components of the complex-valued function \$H(f)\$ versus frequency (this latter in logarithmic units), i.e.:

The plots of $$ 20\cdot \log_{10}|H(f)| $$ and $$ \arg(H(f)) $$ versus logarithmic frequency are the Bode magnitude plot and the Bode phase plot respectively.

See also Wikipedia on Bode plots.

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What are some insights from looking at Bode plots

After studying this in school, the entire concept of a Bode plot still seems to be as a bit of a let down for me given how much emphasis is placed upon it, how often this tool is rumored to be used in the workplace and how little it actually seems…
Fraïssé
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Practical ways to obtain Bode plots for an unknown circuit

I want to use a practical method/way where I can obtain roughly the Bode plot of a system especially a filter. This of course can be done by using complex math or implementing the circuit in a SPICE simulator. But these requires knowing the circuit…
user16307
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Draw Bode-Plot of a transfer function

I want to draw the bode plot of a tranfer function: $$ H(j\omega)=\frac{100j\omega T}{j\omega T + 10}, T=1s $$ Now I have $$ H(j\omega)=\frac{100}{1 + \frac{10}{j\omega T}}, T=1s $$ Using a double log…
Sam
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What's the meaning of a Bode Plot when talking about nonperiodic inputs?

The bode plot itself is built based on a transfer function, regardless of the input signal that will excite the circuit. Based on what I've learned, the bode plot show us how the response amplitude and phase will react when we change the input's…
felipeek
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How can a Bode plot be like that?

Can you do explain how to draw a Bode plot with GH(s)? How do I get the slope and intersection point? This is one of the teacher's examples. He drew it but I don't know what it means. Can you explain it? I only understood that the gain is 20 log…
RNN master
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Why bode plot of cascade system is not the sum of subsystems?

I have two subsystems which the transfer functions you could see below as g(s) and h(s). According to some references show below, I found that the bode plot of a cascade system should be the sum of subsystems. Then, to comfirm that I implemented…
user5558685
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Does frequency at zero matter?

Consider the following simulate this circuit – Schematic created using CircuitLab $$ H(s) = \frac{sR_2C_1}{1+s(R_1+R_2)C_1}$$ $$ f_z = \frac{1}{2\pi R_2C_1} $$ $$ f_p = \frac{1}{2\pi (R_1+R_2)C_1} $$ I simulated the circuit in LTSPICE with…
Bob Doyle
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Find transfer function from Bode plot

This is my Bode plot The solution manual says the function plotted is $$\frac{s^2+0.02s+1001}{s^2+2s+101)(s^2+20s+10100)}$$ What I know is the Bode plot for $$\frac{s^2+2ζω_ns+ω_n^2}{ω_n^2}$$ and the inverse of that. I can see three peaks at ω=1 ,…
John Katsantas
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System Identification (Linear Passive Circuit)

I'm need to find what's inside the following black box but I'm not sure how to exactly do this. simulate this circuit – Schematic created using CircuitLab I'm thinking that I might use the circuit's bode plot as well as the step and impulse…
codedude
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Bode plot of second order system

I'm looking for a way to do a Bode plot of the following transfer function from this schematic: I tried to find the transfer function and finally got this: \$Z_1=\frac{1}{2\pi R_1 C_1}=159\ \mathrm{kHz}\$ (1st order) \$Z_2=\frac{1}{2\pi R_{EQ}…
exolune
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A two-pole system can never be unstable?

I was reading in some textbooks and places online that a single pole introduces a -90 degree phase shift and that in the phase plot, it never actually reaches -90, it goes asymtotic to it. Similarly, for a two-pole system, it never reaches -180…
AlfroJang80
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How is H(jw) = jw correspond to a slope on bode plot?

I cant understand how H(jw) = jw always intersects at "1" , also how the slope of the line is 20dB, Kindly explain, im having a hard time understanding because in book such stuff is not discussed,only a straight foward graph is given for individual…
calculusnoob
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Why is the Bode plot of 1/s a straight line?

The magnitude of the impedance of a capacitor is \$(\omega C)^{-1}\$. Plotting the impedance vs frequency should be a curve with slope \$-1/(\omega ^2C)\$. Why is it plotted as a straight line with a slope of -20dB/dec? Thanks
DavidG25
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Is my measurement setup correct for the common mode frequency response?

I’m using a USB scope which can be used as also a network analyzer. For a network like a passive filter, to obtain Bode plots one input channel is set for reference the other as output. And the input signal is set and swept by a wave generator…
pnatk
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criteria to consider 180 degree as phase cross over frequency in bode plot

Why 180 degree is taken as phase cross over frequency in bode plot? In bode plot, grid impedance(Zg) and inverter impedance(Zi) is plotted for both magnitude and phase. The frequency at which Zg and Zi crosses in magnitude plot, see the phase in…
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