代数式
F
=
a
+
j
b
F = a +jb
F=a+jb
a,b 分别代表了实部和虚部。
指数式
F
=
∣
F
∣
e
θ
F= |F| e^{\theta}
F=∣F∣eθ
F
F
F 代表了模(幅值),
θ
\theta
θ 代表了角度(相位)
三角函数式
F
=
∣
F
∣
e
j
θ
=
∣
F
∣
(
c
o
s
θ
+
j
s
i
n
θ
)
=
a
+
j
b
F= |F| e^{j\theta} = |F| (cos\theta + jsin\theta) = a + jb
F=∣F∣ejθ=∣F∣(cosθ+jsinθ)=a+jb
极坐标式
F
=
∣
F
∣
e
j
θ
=
∣
F
∣
∠
θ
F= |F| e^{j\theta} = |F| \angle \theta
F=∣F∣ejθ=∣F∣∠θ
在 MATLAB 中,i 和 j 表示基本虚数单位。我们可以使用它们来创建复数,例如 1i+3。另外,还可以通过相关函数确定复数的实部和虚部,并计算相位和角度等其他值。
z = 1+2i
--> z = 1.0000 + 2.0000i
x = [1:4]';
y = [8:-2:2]';
z = x+1i*y
--> z = 4×1 complex
1.0000 + 8.0000i
2.0000 + 6.0000i
3.0000 + 4.0000i
4.0000 + 2.0000i
r = 4;
theta = pi/4;
z = r*exp(1i*theta)
--> z = 2.8284 + 2.8284i
z = complex(3,4)
--> z = 3.0000 + 4.0000i
y = abs(-5)
--> y = 5
y = abs(3+4i)
--> y = 5
z = 2*exp(i*0.5)
--> z = 1.7552 + 0.9589i
r = abs(z)
--> r = 2
theta = angle(z)
--> theta = 0.5000
Z = 2+3i
--> Z = 2.0000 + 3.0000i
Zc = conj(Z)
--> Zc = 2.0000 - 3.0000i
X = real(Z) 返回数组 Z 中每个元素的实部。
Z = 2+3i;
X = real(Z)
--> X = 2
Z = [0.5i 1+3i -2.2];
X = real(Z)
--> X = 1×3
0 1.0000 -2.2000
Z = 2+3i;
Y = imag(Z)
--> Y = 3
Z = [0.5i 1+3i -2.2];
Y = imag(Z)
--> Y = 1×3
0.5000 3.0000 0
isreal(z)
--> ans = logical
0