同济大学数字信号处理课件第3章4离散傅里叶变换的性质.ppt
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四、离散傅里叶变换的性质
DFT正变换和反变换:
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1、线性:
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2、序列的圆周移位
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有限长序列的圆周移位导致频谱线性相移,而对频谱幅度无影响。
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调制特性:
时域序列的调制等效于频域的圆周移位
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3、共轭对称性
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其中:
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定义:
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圆周共轭对称序列满足:
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圆周共轭反对称序列满足:
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