??? ???????DFT(?)

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??? ???????DFT(?)

• Chapter 3
• Discrete Fourier-Transform
• (Part ?)

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• ?????
• ????
• ??????????
• ??
• ??????????

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3.5???????(DFT)
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??????????
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3.5???????(DFT)

• DFT??

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DFT?????
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• DFT?????

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• DFT?????

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• ?????????????,?????????DFT????,?????????,?????????
  ?,???????N??????
• ?????3000Hz,N8
• ?????4000Hz,N8
• ?????4000Hz,N16
• ???????4000Hz,N16?????FFT????
• ??????4?????(??)

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3.5???????(DFT)

• ??

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3.5???????(DFT)

• DFT?Z?????

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• DFT????

?? ???????(DFT)
x(n) X(k)
y(n)ax1(n)bx2(n) Y(k)aX1(k)bX2(k) a?b??? ??
x((nm))N.RN(n) X(k) ??????
x(n ) X((km))N.RN(k) ??????
x(n) X(N-k) ??????DFT
X(N-n) X(k)
x(n) y(n) X(k)Y(k) ????????
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3.5???????(DFT)

• DFT????

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3.5???????(DFT)

• DFT????

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3.5???????(DFT)
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3.5???????(DFT)

• ???????

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• ??????

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3.5???????(DFT)

• DFT?????

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3.5???????(DFT)

• DFT?????

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3.5???????(DFT)
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3.5???????(DFT)

• DFT???

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3.5???????(DFT)

• DFT???????

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3.5???????(DFT)