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For x(n)={2 3 4 5 1 3}, plot the following Discrete Time signals.
1 Answer
| written 9.0 years ago by |

1) x(n-1)
Solution: $n’ = n-1 \\ \therefore n=n’-1$
| n | x(n) | n’ |
|---|---|---|
| -2 | 2 | -3 |
| -1 | 3 | -2 |
| 0 | 4 | -1 |
| 1 | 5 | 0 |
| 2 | 1 | 1 |
| 3 | 3 | 2 |

2) x(n)u(-n)
Solution: $n’ = -n \\ u[n] = 0, n\lt0 \\ = 1, n≥0$
| n | x(n) | u(n’) | x(n)u(-n) |
|---|---|---|---|
| -2 | 2 | 1 | 2 |
| -1 | 3 | 1 | 3 |
| 0 | 4 | 1 | 4 |
| 1 | 5 | 0 | 0 |
| 2 | 1 | 0 | 0 |
| 3 | 3 | 0 | 0 |

3) x(n-1)u(-n-1)
Solution: $n’ = n-1 \\ ∴ n = n’+1$

4) x(-n)u(n)
Solution: n’ = -n
| n | n’ | x(n’) | u(n’) | x(n’)u(n) |
|---|---|---|---|---|
| -2 | 2 | 2 | 1 | 2 |
| -1 | 1 | 3 | 1 | 3 |
| 0 | 0 | 4 | 1 | 4 |
| 1 | -1 | 5 | 0 | 0 |
| 2 | -2 | 1 | 0 | 0 |
| 3 | -3 | 3 | 0 | 0 |

Result: x(-n)u(n) = {4}
5) x(2n)
Solution: $n’ = 2n \\ \therefore n = n’/2$
| n | n’ | x(n’) |
|---|---|---|
| -2 | -1 | 2 |
| -1 | -1/2 | 3 |
| 0 | 0 | 4 |
| 1 | 1/2 | 5 |
| 2 | 1 | 1 |
| 3 | 3/2 | 3 |
