10/09 - Fourier Transform

$⟨ e^{j 2 π n t / T} ∣ e^{j 2 π m t / T} ⟩$	$= \int_{- \infty}^{\infty} e^{j 2 π n t / T} e^{- j 2 π m t / T} d t$
	$= \int_{- \infty}^{\infty} e^{j 2 π (n - m) t / T} d t$
	$= \int_{- T / 2}^{T / 2} e^{j 2 π (n - m) t / T} d t$	Assuming the function is perodic with the period T
	$= T δ_{m, n}$

Fourier Transform