348 Practical MATLAB® Applications for Engineers
e. Differentiation in freq(s)tft
dF s
ds⋅↔()
()
or a more general relation is given by() () 1 nn [()]n
tft n
d
ds↔ Fsf. Differentiation in t
df t
dtsF s f()
↔ () ( ) 0
The second derivative is given byd
dtdf t
dtd
dtft ssFs f fsFs s()
[ ( )] [ ( ) ( )] ( )
()
↔
2
2200
fff() ()00
The preceding process can be repeated for higher-order derivatives.
g. Integration in sft
tFsds()
↔ ()
∞
∫(^0)
h. Periodic functions f(t), with period T > 0
ft
e ftdt
e
T st
() sT
()
()
↔
∫
0(^1)
i. Integration in t
fd sFs
f
() () s
()
01 0
∫ ↔
j. Convolution in t or product in sft 12 ()⊗↔ft() f 12 ( ) (ft )d [ () ()]FsFs 12
∞∞
∫
k. Product in t or convolution in sftft
j
12 Fs 1 Fs 2