Fourier Series for real and odd signals

AI Thread Summary
The discussion centers on the computation of Fourier Series coefficients for real and odd signals, specifically addressing a recurring issue with obtaining coefficients that are inverted on the x-axis. The user initially believes the problem lies in their approach to the integral involving e^(-j*k*w*t) and sin(k*w*t). Upon further reflection, they identify a potential error related to a missing minus sign in their integral calculation. This realization suggests that the correct formulation may involve adjusting the sign in the sine function or the frequency term. The conversation highlights the importance of careful attention to signs in Fourier analysis.
awelex
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Hi,

I have a general question regarding the computation of Fourier Series coefficients for real and odd inputs. In this case, the following should be true:

∫x(t)*e^(-j*k*w*t)dt = ∫x(t)*sin(k*w*t)dt

However, every time I compute my coefficients this way, I get the inverse sign of what it is supposed to be -- my coefficients are flipped on the x-axis. Since this happens every time, I don't think it's a computational mistake, but rather a conceptual problem. What am I doing wrong?

Thanks.
 
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A second after posting this, I think I figured it out:

Since e^(-j*w*t) = cos(w*t) - j * sin(w*t), I'm missing a minus sign in my integral. Correct?
 
It's either that, else or your integral should be ∫x(t)*sin(k*-w*t)dt :smile:
 
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