Z Transform Delta
1. **Problem Statement:** Determine the Z-transform of the finite duration signals given by:
(e) $x_5(n) = \delta(n)$
(f) $x_6(n) = \delta(n - k), k > 0$
(g) $x_7(n) = \delta(n + k), k > 0$
2. **Recall the Z-transform definition:**
The Z-transform of a discrete-time signal $x(n)$ is defined as:
$$X(z) = \sum_{n=-\infty}^{\infty} x(n) z^{-n}$$
3. **Important property of the delta function:**
The delta function $\delta(n - n_0)$ is zero everywhere except at $n = n_0$, where it equals 1.
4. **Calculate each Z-transform:**
(e) For $x_5(n) = \delta(n)$:
$$X_5(z) = \sum_{n=-\infty}^{\infty} \delta(n) z^{-n} = z^{0} = 1$$
(f) For $x_6(n) = \delta(n - k), k > 0$:
$$X_6(z) = \sum_{n=-\infty}^{\infty} \delta(n - k) z^{-n} = z^{-k}$$
(g) For $x_7(n) = \delta(n + k), k > 0$:
$$X_7(z) = \sum_{n=-\infty}^{\infty} \delta(n + k) z^{-n}$$
Since $\delta(n + k)$ is 1 at $n = -k$,
$$X_7(z) = z^{k}$$
5. **Summary:**
- $X_5(z) = 1$
- $X_6(z) = z^{-k}$
- $X_7(z) = z^{k}$
These results show how the delta function shifts affect the powers of $z$ in the Z-transform.