Notation_Table.md

Concept	Oppenheim & Willsky	Roberts	Haykin & van Veen	Hsu
Continuous-time signal	$x(t)$
Discrete-time signal (sequence)	$x[n]$
Continuous-time Fourier transform signal	$X(j\omega)$
Discrete-time Fourier transform signal	$X(e^{j\omega})$
Convolution sum
Modulo operation