ID
Función
Dominio en el tiempo
x
(
t
)
=
L
−
1
{
X
(
s
)
}
{\displaystyle x(t)={\mathcal {L}}^{-1}\left\{X(s)\right\}}
Dominio en la frecuencia
X
(
s
)
=
L
{
x
(
t
)
}
{\displaystyle X(s)={\mathcal {L}}\left\{x(t)\right\}}
Región de la convergencia para sistemas causales
1
retraso ideal
δ
(
t
−
τ
)
{\displaystyle \delta (t-\tau )\ }
e
−
τ
s
{\displaystyle e^{-\tau s}\ }
1a
impulso unitario
δ
(
t
)
{\displaystyle \delta (t)\ }
1
{\displaystyle 1\ }
t
o
d
o
s
{\displaystyle \mathrm {todo} \ s\,}
2
enésima potencia retrasada y con desplazamiento en la frecuencia
(
t
−
τ
)
n
n
!
e
−
α
(
t
−
τ
)
⋅
u
(
t
−
τ
)
{\displaystyle {\frac {(t-\tau )^{n}}{n!}}e^{-\alpha (t-\tau )}\cdot u(t-\tau )}
e
−
τ
s
(
s
+
α
)
n
+
1
{\displaystyle {\frac {e^{-\tau s}}{(s+\alpha )^{n+1}}}}
s
>
−
α
{\displaystyle s>-\alpha \,}
2a
n-ésima potencia
t
n
n
!
⋅
u
(
t
)
{\displaystyle {t^{n} \over n!}\cdot u(t)}
1
s
n
+
1
{\displaystyle {1 \over s^{n+1}}}
s
>
0
{\displaystyle s>0\,}
2a.1
q-ésima potencia
t
q
Γ
(
q
+
1
)
⋅
u
(
t
)
{\displaystyle {t^{q} \over \Gamma (q+1)}\cdot u(t)}
1
s
q
+
1
{\displaystyle {1 \over s^{q+1}}}
s
>
0
{\displaystyle s>0\,}
2a.2
escalón unitario
u
(
t
)
{\displaystyle u(t)\ }
1
s
{\displaystyle {1 \over s}}
s
>
0
{\displaystyle s>0\,}
2b
escalón unitario con retraso
u
(
t
−
τ
)
{\displaystyle u(t-\tau )\ }
e
−
τ
s
s
{\displaystyle {e^{-\tau s} \over s}}
s
>
0
{\displaystyle s>0\,}
2c
Rampa
t
⋅
u
(
t
)
{\displaystyle t\cdot u(t)\ }
1
s
2
{\displaystyle {\frac {1}{s^{2}}}}
s
>
0
{\displaystyle s>0\,}
2d
potencia n-ésima con cambio de frecuencia
t
n
n
!
e
−
α
t
⋅
u
(
t
)
{\displaystyle {\frac {t^{n}}{n!}}e^{-\alpha t}\cdot u(t)}
1
(
s
+
α
)
n
+
1
{\displaystyle {\frac {1}{(s+\alpha )^{n+1}}}}
s
>
−
α
{\displaystyle s>-\alpha \,}
2d.1
amortiguación exponencial
e
−
α
t
⋅
u
(
t
)
{\displaystyle e^{-\alpha t}\cdot u(t)\ }
1
s
+
α
{\displaystyle {1 \over s+\alpha }}
s
>
−
α
{\displaystyle s>-\alpha \ }
3
convergencia exponencial
(
1
−
e
−
α
t
)
⋅
u
(
t
)
{\displaystyle (1-e^{-\alpha t})\cdot u(t)\ }
α
s
(
s
+
α
)
{\displaystyle {\frac {\alpha }{s(s+\alpha )}}}
s
>
0
{\displaystyle s>0\ }
3b
exponencial doble
1
b
−
a
(
e
−
a
t
−
e
−
b
t
)
{\displaystyle {\frac {1}{b-a}}\left(e^{-at}-e^{-bt}\right)}
1
(
s
+
a
)
(
s
+
b
)
{\displaystyle {\frac {1}{(s+a)(s+b)}}}
s
>
−
a
y
s
>
−
b
{\displaystyle s>-a\ y\ s>-b\ }
4
seno
sin
(
ω
t
)
⋅
u
(
t
)
{\displaystyle \sin(\omega t)\cdot u(t)\ }
ω
s
2
+
ω
2
{\displaystyle {\omega \over s^{2}+\omega ^{2}}}
s
>
0
{\displaystyle s>0\ }
5
coseno
cos
(
ω
t
)
⋅
u
(
t
)
{\displaystyle \cos(\omega t)\cdot u(t)\ }
s
s
2
+
ω
2
{\displaystyle {s \over s^{2}+\omega ^{2}}}
s
>
0
{\displaystyle s>0\ }
5b
seno con fase
sin
(
ω
t
+
φ
)
⋅
u
(
t
)
{\displaystyle \sin(\omega t+\varphi )\cdot u(t)}
s
sin
(
φ
)
+
ω
cos
φ
s
2
+
ω
2
{\displaystyle {\frac {s\sin(\varphi )+\omega \cos \varphi }{s^{2}+\omega ^{2}}}}
s
>
0
{\displaystyle s>0\ }
6
seno hiperbólico
sinh
(
α
t
)
⋅
u
(
t
)
{\displaystyle \sinh(\alpha t)\cdot u(t)\ }
α
s
2
−
α
2
{\displaystyle {\alpha \over s^{2}-\alpha ^{2}}}
s
>
|
α
|
{\displaystyle s>|\alpha |\ }
7
coseno hiperbólico
cosh
(
α
t
)
⋅
u
(
t
)
{\displaystyle \cosh(\alpha t)\cdot u(t)\ }
s
s
2
−
α
2
{\displaystyle {s \over s^{2}-\alpha ^{2}}}
s
>
|
α
|
{\displaystyle s>|\alpha |\ }
8
onda senoidal con amortiguamiento exponencial
e
−
α
t
sin
(
ω
t
)
⋅
u
(
t
)
{\displaystyle e^{-\alpha t}\sin(\omega t)\cdot u(t)\ }
ω
(
s
+
α
)
2
+
ω
2
{\displaystyle {\omega \over (s+\alpha )^{2}+\omega ^{2}}}
s
>
−
α
{\displaystyle s>-\alpha \ }
9
onda cosenoidal con amortiguamiento exponencial
e
−
α
t
cos
(
ω
t
)
⋅
u
(
t
)
{\displaystyle e^{-\alpha t}\cos(\omega t)\cdot u(t)\ }
s
+
α
(
s
+
α
)
2
+
ω
2
{\displaystyle {s+\alpha \over (s+\alpha )^{2}+\omega ^{2}}}
s
>
−
α
{\displaystyle s>-\alpha \ }
10
raíz n-ésima
t
n
⋅
u
(
t
)
{\displaystyle {\sqrt[{n}]{t}}\cdot u(t)}
s
−
(
n
+
1
)
/
n
⋅
Γ
(
1
+
1
t
)
{\displaystyle s^{-(n+1)/n}\cdot \Gamma \left(1+{\frac {1}{t}}\right)}
s
>
0
{\displaystyle s>0\,}
11
logaritmo natural
ln
(
t
t
0
)
⋅
u
(
t
)
{\displaystyle \ln \left({t \over t_{0}}\right)\cdot u(t)}
−
t
0
s
[
ln
(
t
0
s
)
+
γ
]
{\displaystyle -{t_{0} \over s}\ [\ \ln(t_{0}s)+\gamma \ ]}
s
>
0
{\displaystyle s>0\,}
12
Función de Bessel de primer tipo, de orden n
J
n
(
ω
t
)
⋅
u
(
t
)
{\displaystyle J_{n}(\omega t)\cdot u(t)}
ω
n
(
s
+
s
2
+
ω
2
)
−
n
s
2
+
ω
2
{\displaystyle {\frac {\omega ^{n}\left(s+{\sqrt {s^{2}+\omega ^{2}}}\right)^{-n}}{\sqrt {s^{2}+\omega ^{2}}}}}
s
>
0
{\displaystyle s>0\,}
(
n
>
−
1
)
{\displaystyle (n>-1)\,}
13
Función de Bessel modificada de primer tipo, de orden n
I
n
(
ω
t
)
⋅
u
(
t
)
{\displaystyle I_{n}(\omega t)\cdot u(t)}
ω
n
(
s
+
s
2
−
ω
2
)
−
n
s
2
−
ω
2
{\displaystyle {\frac {\omega ^{n}\left(s+{\sqrt {s^{2}-\omega ^{2}}}\right)^{-n}}{\sqrt {s^{2}-\omega ^{2}}}}}
s
>
|
ω
|
{\displaystyle s>|\omega |\,}
14
Función de Bessel de segundo tipo, de orden 0
Y
0
(
α
t
)
⋅
u
(
t
)
{\displaystyle Y_{0}(\alpha t)\cdot u(t)}
15
Función de Bessel modificada de segundo tipo, de orden 0
K
0
(
α
t
)
⋅
u
(
t
)
{\displaystyle K_{0}(\alpha t)\cdot u(t)}
16
Función de error
e
r
f
(
t
)
⋅
u
(
t
)
{\displaystyle \mathrm {erf} (t)\cdot u(t)}
e
s
2
/
4
erfc
(
s
/
2
)
s
{\displaystyle {e^{s^{2}/4}\operatorname {erfc} \left(s/2\right) \over s}}
s
>
0
{\displaystyle s>0\,}
Notas explicativas:
t
{\displaystyle t\,}
, un número real, típicamente representa tiempo , aunque puede representar cualquier variable independiente.
s
{\displaystyle s\,}
es la frecuencia angular compleja .
α
{\displaystyle \alpha \,}
,
β
{\displaystyle \beta \,}
,
τ
{\displaystyle \tau \,}
, y
ω
{\displaystyle \omega \,}
son números reales .
n
{\displaystyle n\,}
es un número entero .
sistema causal es un sistema donde la respuesta al impulso h (t ) es cero para todo tiempo t anterior a t = 0. En general, el ROC para sistemas causales no es el mismo que el ROC para sistemas anticausales . Véase también causalidad .