ifftnGydF4y2Ba
多维逆快速傅立叶变换GydF4y2Ba
句法GydF4y2Ba
Description
X=ifftn((GydF4y2Ba
返回GydF4y2Ba多维离散逆傅立叶变换GydF4y2Baof an N-D array using a fast Fourier transform algorithm. The N-D inverse transform is equivalent to computing the 1-D inverse transform along each dimension ofyGydF4y2Ba
)GydF4y2BayGydF4y2Ba
。这outputXGydF4y2Ba
一世s the same size asyGydF4y2Ba
。GydF4y2Ba
X=ifftn((GydF4y2Ba
截断GydF4y2BayGydF4y2Ba
,,,,GydF4y2BaSZGydF4y2Ba
)GydF4y2BayGydF4y2Ba
或垫子GydF4y2BayGydF4y2Ba
with trailing zeros before taking the inverse transform according to the elements of the vectorSZGydF4y2Ba
。Each element ofSZGydF4y2Ba
定义相应变换维度的长度。例如,如果GydF4y2BayGydF4y2Ba
一世s a 5-by-5-by-5 array, thenx = ifftn(y,[8 8 8])GydF4y2Ba
用零填充每个维度,导致8 x 8 x-8的逆变换GydF4y2BaXGydF4y2Ba
。GydF4y2Ba
X=ifftn((GydF4y2Ba___GydF4y2Ba,,,,GydF4y2Ba
指定对称性的对称性GydF4y2BaSymflagGydF4y2Ba
)GydF4y2BayGydF4y2Ba
一世n addition to any of the input argument combinations in previous syntaxes. For example,ifftn(y,'对称')GydF4y2Ba
treatsyGydF4y2Ba
作为对称的共轭。GydF4y2Ba
Examples
输入参数GydF4y2Ba
更多关于GydF4y2Ba
Algorithms
这GydF4y2Ba
ifftnGydF4y2Ba
功能测试是否多维数组GydF4y2BayGydF4y2Ba
是对称的。如果GydF4y2BayGydF4y2Ba
是共轭对称的,然后逆变换计算更快,输出是真实的。GydF4y2BaA function 如果是对称的GydF4y2Ba 。However, the fast Fourier transform of a multidimensional time-domain signal has one half of its spectrum in positive frequencies and the other half in negative frequencies, with the first row, column, page, and so on, reserved for the zero frequencies. For this reason, for example, a 3-D array
yGydF4y2Ba
一世s conjugate symmetric when all of these conditions are true:y(1,1,2:结束)GydF4y2Ba
是对称的,或GydF4y2Bay(1,1,2:结束)=Conj(Y(1,1,end:-1:2))
y(1,2:end,1)GydF4y2Ba
是对称的,或GydF4y2Bay(1,2:end,1)= conj(y(1,结束:-1:2,1))GydF4y2Ba
Y(2:End,1,1)GydF4y2Ba
是对称的,或GydF4y2BaY(2:End,1,1)=Conj(Y(end:-1:2,1,1))
y(1,2:end,2:end)GydF4y2Ba
一世s conjugate centrosymmetric, ory(1,2:end,2:end)= conj(y(1,结束:-1:2,结束:-1:2))GydF4y2Ba
y(2:end,1,2:end)GydF4y2Ba
一世s conjugate centrosymmetric, ory(2:end,1,2:end)= conj(y(结束:-1:2,1,结束:-1:2))GydF4y2Ba
y(2:end,2:end,1)GydF4y2Ba
一世s conjugate centrosymmetric, ory(2:end,2:end,1)=Conj(Y(end:-1:2,end:-1:2,1))
y(2:end,2:end,2:end)GydF4y2Ba
一世s conjugate centrosymmetric, ory(2:end,2:end,2:end)=Conj(Y(end:-1:2,end:-1:2,end:-1:2))
扩展功能GydF4y2Ba
版本历史记录GydF4y2Ba
也可以看看GydF4y2Ba
ifft2GydF4y2Ba
|GydF4y2BaifftGydF4y2Ba
|GydF4y2Baifftshift
|GydF4y2BaFFTNGydF4y2Ba
|GydF4y2Bafftw