- #1
seanbow
- 2
- 0
Say you have the coefficients a_k of a Fourier series representation of some function x(t). You can easily then give x(t) as
$$x(t) = \sum_{k = -\infty}^{\infty} a_k e^{i k \omega_0 t}$$
But this doesn't do much good in telling you what the actual function looks like. For example, if we have
$$a_k = \frac{ \sin ( k \pi / 2)} {k \pi}$$
we can write x(t) as
x(t) = \sum_{k \neq 0} \frac{ \sin (k \pi / 2)} {k \pi} e^{i k \omega_0 t}
but you would have a hard time telling that this is a square wave with a duty cycle of 50% unless you've previously derived the series coefficients for that exact function.
Basically, my question is: is there a way to derive a more intuitive representation of a function given its Fourier series representation?
$$x(t) = \sum_{k = -\infty}^{\infty} a_k e^{i k \omega_0 t}$$
But this doesn't do much good in telling you what the actual function looks like. For example, if we have
$$a_k = \frac{ \sin ( k \pi / 2)} {k \pi}$$
we can write x(t) as
x(t) = \sum_{k \neq 0} \frac{ \sin (k \pi / 2)} {k \pi} e^{i k \omega_0 t}
but you would have a hard time telling that this is a square wave with a duty cycle of 50% unless you've previously derived the series coefficients for that exact function.
Basically, my question is: is there a way to derive a more intuitive representation of a function given its Fourier series representation?
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