Can anyone help me with fourier series of a signal?
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I got a signal as attached. My doubt is can I break the signal in a triangle and a straight line, then calculating fourier series for each. Will this break may affect my answer (magnitude * frequency)
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Image Analyst
2016년 8월 12일
I meant post it here with the green and brown frame icon. Here, I will do it for you:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/184358/image.png)
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Star Strider
2016년 8월 11일
If you’re doing a numeric fft, do the Fourier Transform of the entire signal.
To do it symbolically, separate it into two segments for each part of the triangle, and add:
syms w t f1(t) f2(t)
f1(t) = 40*t;
f2(t) = 40-40*t;
F(w) = int(f1(t)*exp(1i*w*t), t, 0, 0.5) + int(f2(t)*exp(1i*w*t), t, 0.5, 1);
F(w) = simplify(F(w), 'steps',20)
F(w) =
-(40*(exp((w*1i)/2) - 1)^2)/w^2
It is zero elsewhere, so you can ignore that section.
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Star Strider
2016년 8월 12일
My pleasure.
Your code is very difficult to follow. Instead of using separate sine and cosine terms, I would use the complex exponential to calculate the Fourier transform.
For a single pulse, you can ignore the zero segment. If your pulse repeats at regular intervals, you must include at least two pulses, with the pulses defined just as the first one was, as segments of straight lines (in this example), each with appropriate slopes and intercepts and integrated over the appropriate time intervals. The zero-value interval is implicit in those integrations, but does not have to be specifically included.
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