이번에도 링크;

Parseval's Theorem(Parseval's Formula)
http://mathworld.wolfram.com/ParsevalsTheorem.html

Poisson Sum Formula
http://mathworld.wolfram.com/PoissonSumFormula.html

Fast Fourier Transform(FFT)
http://mathworld.wolfram.com/FastFourierTransform.html

Fast Fourier Transform 때문에 머리 빠지겠다 ㅠㅠ

여튼 mathworld 쵝오~