Laplace Transform Properties
Property Signal Laplace Transform ROC
Linearity $ \,\! ax_1(t) + bx_2(t) $ $ \,\! aX_1(s)+bX_2(s) $ At least $ R_1 \cap R_2 $
Time Shifting $ \,\! x(t-t_0) $ $ e^{-st_0}X(s) $ R
Shifting in the s-Domain $ e^{s_0 t}x(t) $ $ \,\! X(s-s_0) $ Shifted version of R (i.e., s is in the ROC if $ s - s_0 $ is in R)
Time scaling $ \,\! x(at) $ $ \frac{1}{|a|}X\Bigg( \frac{s}{a} \Bigg) $ Scaled ROC (i.e., s is in the ROC if s/a is in R)
Conjugation $ \,\! x^{*}(t) $ $ \,\! X^{*}(s^{*}) $ R
Convolution $ \,\! x_1(t)*x_2(t) $ $ \,\! X_1(s)X_2(s) $ At least $ R_1 \cap R_2 $
Differentiation in the Time Domain $ \frac{d}{dt}x(t) $ $ \,\! sX(s) $ At least R
Differentiation in the s-Domain $ \,\! -tx(t) $ $ \frac{d}{ds}X(s) $ R
Integration in the Time Domain $ \int_{-\infty}^{t}x(\tau)\,d\tau $ $ \frac{1}{s}X(s) $ At least $ R \cap \lbrace \mathcal{R} \mathfrak{e} \lbrace s \rbrace > 0 \rbrace $
$ \,\!\mbox{Initial- and Final-Value Theorem} $
$ \,\!\mbox{If } x(t) = 0 \mbox{ for } t < 0 \mbox{ and } x(t)\mbox{ contains} $ 

$ \,\! \mbox{no impulses or higher-order singularities at }t = 0\mbox{, then} $

$ x(0^{+}) = \lim_{x\rightarrow \infty} sX(s) $
$ \lim_{t\rightarrow \infty} x(t) = \lim_{s\rightarrow 0}sX(s) $

Alumni Liaison

Sees the importance of signal filtering in medical imaging

Dhruv Lamba, BSEE2010