0
2.0kviews
Find DFT of x(n)={1234} Using these results and not otherwise find DFT.
1 Answer
0
80views

1]

x1(n)={4123}x2(n)={2341}x3(n)={6464}

Solution:

Given:

x(n)={1,2,3,4}

By definition of DFT.

x(k)=N1n=0x(n)wnkN K=0,1,,N1

x(k)=[11111j1j11111j1j][1234]

x(k)=[102+2i222j]

x1(n)={4,1,2,3}

x1(n)=x(n1)

By using time shift

x1(k)=ej2πlkNx(k)

Here L = 1

x1(k)=ej2πR4x(k)

x1(k)=ejπR/2x(k)

x1(0)=x(0)=10

x1(1)=ejπ/2x(2)=j(2+2j)=2+2j

x2(2)=ej2π/2x(2)=1(2)=2

x1(3)=ej3π/2x(3)=j(22j)=22j

x1(k)=[102+2j222j]

x2(n)={2341}

x2(n)=x(n+1)

By time shift property

X2(k)=ej2πk4x(r)

x2(b)=ejπk2x(R)

x2(0)=x(0)=10

x2(1)=ejπ/2x(1)=+j(2+2j)=22j

x2(2)=ejπx(2)=1(2)=2

x2(3)=ej3π/2x(3)=j(22j)=2+2j

x3(n)={6,4,6,4}

x3(n)=x(n+1)+x(n1)

By linearity and Time shift prop.

X3(k)=ej2πR4x(k)+ejπk4x(R)

=eπR4x(R)+ejπk2x(k)

=[10+2+2j222j]+[1022j22+2j]

x3(x)=[20040]

Please log in to add an answer.