Fourier Series / Fourier Transform Question

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Discussion Overview

The discussion revolves around a question related to Fourier series and Fourier transforms, specifically focusing on sketching a triangular pulse and obtaining its frequency spectrum. The context includes aspects of exam preparation and signal analysis.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes a triangular pulse defined by specific equations for different intervals of time and expresses uncertainty about obtaining the frequency spectrum.
  • Another participant raises an ethical concern regarding seeking help with an exam question.
  • A later reply clarifies that the question is from a previous exam, suggesting that it may not violate exam integrity.
  • One participant inquires whether obtaining the frequency spectrum involves calculating the Fourier coefficients and plotting their magnitudes.
  • Another participant suggests that computing the Fourier transform should be straightforward, regardless of the method used (sines & cosines or complex exponentials).

Areas of Agreement / Disagreement

Participants express differing views on the appropriateness of seeking help for exam questions, and there is no consensus on the difficulty of computing the Fourier transform or the best approach to sketching the frequency spectrum.

Contextual Notes

Some participants mention the complexity of the integration involved in calculating the Fourier transform, indicating potential limitations in their understanding or approach to the problem.

SpeedBird
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Hello there,

Im sure someone on this forum must know how to go about this.
It is part of an exam question.

Firstly I must draw a sketch of this pulse:

v=0 when |t| > a
v=V0( 1 + t/a ) when -a < t <= 0
v=V0( 1 - t/a ) when 0 < t < a

v represents amplitude, V0 represents peak amplitude, t represents
time and 'a' is a constatnt.

i can draw the pulse ok, it is just a triangular pulse that goes from
0 at t = +a and -a to V0 when t = 0.

The bit I am unsure about is obtaining and sketching the frequency
spectrum of this pulse. Any ideas?

Thanks,

Nik
 
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Isn't there an ethics problem with getting assistance with an exam question?
 
maybe if i was in the exam at the time. :smile:
it's a question from last years signal analysis exam.
thanks anyway!
 
Last edited:
does anyone have any ideas?
 
Well, have you computed the Fourier transform?
 
i havnt computed the FT. the integration is huge and i get stuck pretty quickly. do you think getting the Freq spectrum could mean getting [tex]a_k[/tex] and [tex]b_k[/tex] coefficients for the Fourier series and plotting their magnitudes against [tex]k[/tex]?
 
Last edited:
I'm having difficulty seeing the trouble -- the integral should be something straight out of a calc II class, whether you use sines & cosines as your basis, or you use complex exponentials.
 

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