通用：
∣
e
j
w
t
∣
|e^{jwt}|
∣ejwt∣
p
∞
=
1
=
e
j
θ
p_{\infty}=1=e^{j\theta}
p∞=1=ejθ
e
j
θ
=
c
o
s
θ
+
j
s
i
n
θ
e^{j\theta}=cos\theta+jsin\theta
ejθ=cosθ+jsinθ
c
o
s
θ
—
>
p
∞
=
1
/
2
cos\theta—>p_{\infty}=1/2
cosθ—>p∞=1/2
s
i
n
θ
—
>
p
∞
=
1
/
2
sin\theta—>p_{\infty}=1/2
sinθ—>p∞=1/2