複素フーリエ級数：$f(t)=\displaystyle\sum^{\infty}_{n=-\infty}c_n e^{j2\pi nt/T}$
但し，$c_n=\displaystyle\frac{1}{T}\displaystyle\int^{T}_{0}f(t)e^{-j2\pi nt/T}dt$
櫛関数：$f(t)=\mbox{comb}(t)=\displaystyle\sum^{\infty}_{n=-\infty}\delta(t-n)$
フーリエ係数：$c_n=\displaystyle\int^{1}_{0}\delta(t)e^{-j2\pi nt}dt=1 \,\,\,∵T=1$
$\mbox{comb}(t)=\displaystyle\sum^{\infty}_{n=-\infty}e^{j2\pi nt}$ $=\displaystyle\sum^{-1}_{n=-\infty}e^{j2\pi nt}+1+\displaystyle\sum^{\infty}_{n=1}e^{j2\pi nt}$ $=1+\displaystyle\sum^{\infty}_{n=1}e^{-j2\pi nt} +\displaystyle\sum^{\infty}_{n=1}e^{j2\pi nt}$
$\underline{=1+2\displaystyle\sum^{\infty}_{n=1} \mbox{cos}(2\pi nt)}$