Sketch the response of a system(bode plot given) to two inputs

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Discussion Overview

The discussion revolves around sketching the response of a system based on a given Bode plot and two input signals. Participants explore the relationship between the input signals, their characteristics, and how to derive the system's response from the provided diagrams.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants calculate the damping ratio from the magnitude diagram, estimating it to be approximately 0.16, but express uncertainty about further steps.
  • There is a question about whether the input plots are continuous or truncated at a specific time, which could affect the analysis.
  • Participants discuss the nature of the input signals, identifying them as sine waveforms and questioning what parameters define a sine wave.
  • One participant suggests that the task may involve plotting the output for each input signal separately rather than combining them, emphasizing the importance of demonstrating phase differences.
  • Another participant outlines an equation for the response wave, detailing the parameters involved and how they relate to the Bode plot, seeking confirmation of their understanding.
  • There is a discussion about the interpretation of the Bode plot's magnitude and its implications for the calculations needed to sketch the response.
  • Participants engage in clarifying the expression used in the Bode magnitude diagram and the meaning of the variable K in the context of their calculations.

Areas of Agreement / Disagreement

Participants express various viewpoints on how to approach the problem, with no consensus on the exact method to sketch the response or the interpretation of the Bode plot. Some participants agree on the need to analyze the input signals separately, while others focus on the damping ratio and its relevance.

Contextual Notes

There are unresolved questions regarding the specific characteristics of the input signals and the implications of the Bode plot readings, particularly in terms of how to apply them to the response sketching process.

legolegoyoyo
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Hi all
Please help me with this question, thanks a lot.
7464930188_dbb23a915a_b.jpg

7464930048_cb14610b6c_b.jpg

My attempt on this question is that i can calculate the damping ratio from the magnitude diagram, approximately 0.16
I can't do more than that, please help. I will be grateful even if you pointing me a direction solving this.
cheers
 
Last edited:
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legolegoyoyo said:
Hi all
Please help me with this question, thanks a lot.
7464930188_dbb23a915a_b.jpg

7464930048_cb14610b6c_b.jpg




My attempt on this question is that i can calculate the damping ratio from the magnitude diagram, approximately 0.16
I can't do more than that, please help. I will be grateful even if you pointing me a direction solving this.
cheers

Hint: What type of signals (waveforms) are the inputs? What are the basic defining characteristics of such signals?
 
Your two input plots are the same.
Are they intended to be continuous or stop at t = 10? If continuous the answer should bite you on the nose. If truncated at 10 sec. then you have a bigger challenge. Tell us which, and what happened to the second input plot.
 
thank you for the reply, the question asks to draw response on the input diagram.
 
gneill said:
Hint: What type of signals (waveforms) are the inputs? What are the basic defining characteristics of such signals?

hi
I'm not sure what information should i get from the bode plot and the input signal to sketch the response.

to your question, the signal is sine wave form
:smile:
 
legolegoyoyo said:
hi
I'm not sure what information should i get from the bode plot and the input signal to sketch the response.

to your question, the signal is sine wave form
:smile:

What parameters define a sinewave?
 
gneill said:
What parameters define a sinewave?

Hi:smile:
period, amplitude,
 
I doubt that the question is asking for you to draw a waveform that is a composite of two. I'd say you are to first consider one of the inputs and plot the corresponding output on the same set of axes as that input. Then as a separate question, consider the other signal as input, and sketch the corresponding output, again on the same plot as the input so you can demonstrate the phase difference.

There is no requirement to determine damping ratio, that I can see.

Are you right to go now, legolegoyoyo?
 
NascentOxygen said:
I doubt that the question is asking for you to draw a waveform that is a composite of two. I'd say you are to first consider one of the inputs and plot the corresponding output on the same set of axes as that input. Then as a separate question, consider the other signal as input, and sketch the corresponding output, again on the same plot as the input so you can demonstrate the phase difference.

There is no requirement to determine damping ratio, that I can see.

Are you right to go now, legolegoyoyo?

Hi, thanks for the reply, its very helpful
there is an equation from my lecture notes,

y(t)=AMsin(ω0t+∅)
the 2 input signal graph are just 2 different input, and the question requires to sketch on them individually
my understanding to this equation is,

y(t) is the response wave
A is the amplitude of the input signal
M is the magnitude read from the bode diagram(magnitude diagram) at the frequency of ω0
ω0 is the frequency(in rad/s) read from the input signal and convert to rad/s by multiply the frequency(in Hz) with 2[itex]\pi[/itex]
∅ is the angle read from bode diagram(phase diagram) at the frequency of ω0
then i just substitute all the values i got into the equation y(t) to get the response wave plot

Im i correct? Please comment
cheers mate!
 
  • #10
legolegoyoyo said:
Hi, thanks for the reply, its very helpful
there is an equation from my lecture notes,

y(t)=AMsin(ω0t+∅)
the 2 input signal graph are just 2 different input, and the question requires to sketch on them individually
my understanding to this equation is,

y(t) is the response wave
A is the amplitude of the input signal
M is the magnitude read from the bode diagram(magnitude diagram) at the frequency of ω0
ω0 is the frequency(in rad/s) read from the input signal and convert to rad/s by multiply the frequency(in Hz) with 2[itex]\pi[/itex]
∅ is the angle read from bode diagram(phase diagram) at the frequency of ω0
then i just substitute all the values i got into the equation y(t) to get the response wave plot

Im i correct? Please comment
cheers mate!

Yup, it looks like you're on your way. One thing though, make sure that you understand precisely what the Bode plot "Magnitude" is...
 
  • #11
gneill said:
Yup, it looks like you're on your way. One thing though, make sure that you understand precisely what the Bode plot "Magnitude" is...

Thank to you for your hints:wink:

for the quote, did you mean i need to anti log the reading from magnitude bode diagram
 
  • #12
legolegoyoyo said:
Thank to you for your hints:wink:

for the quote, did you mean i need to anti log the reading from magnitude bode diagram

When you're drawing a bode magnitude diagram, what expression are you plotting against angular frequency?
 
  • #13
gneill said:
When you're drawing a bode magnitude diagram, what expression are you plotting against angular frequency?

20logK
 
  • #14
legolegoyoyo said:
20logK

And what's K in this context?
 
  • #15
gneill said:
and what's k in this context?

10m/20
 
  • #16
legolegoyoyo said:
10m/20

Perhaps I should have been more specific; I wasn't looking for you to isolate K but rather to state what K represents in the given formula.
 

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