Z-Transforms

Description: This quiz will test your understanding of Z-Transforms, a mathematical tool used to analyze discrete-time signals and systems.
Number of Questions: 14
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Tags: z-transforms discrete-time signals systems analysis
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What is the Z-Transform of the sequence (x[n] = a^n), where (a) is a constant?

  1. (X(z) = \frac{z}{z - a})

  2. (X(z) = \frac{z}{z + a})

  3. (X(z) = \frac{1}{z - a})

  4. (X(z) = \frac{1}{z + a})


Correct Option: A
Explanation:

The Z-Transform of (x[n] = a^n) is (X(z) = \sum_{n=0}^\infty a^n z^{-n} = \frac{z}{z - a}).

What is the Z-Transform of the unit step sequence (u[n])?

  1. (U(z) = \frac{1}{1 - z^{-1}})

  2. (U(z) = \frac{z}{z - 1})

  3. (U(z) = \frac{1}{z - 1})

  4. (U(z) = \frac{z}{1 - z^{-1}})


Correct Option: A
Explanation:

The Z-Transform of (u[n]) is (U(z) = \sum_{n=0}^\infty z^{-n} = \frac{1}{1 - z^{-1}}).

What is the Z-Transform of the sequence (x[n] = n)?

  1. (X(z) = \frac{z}{(z - 1)^2})

  2. (X(z) = \frac{z^2}{(z - 1)^2})

  3. (X(z) = \frac{1}{(z - 1)^2})

  4. (X(z) = \frac{z}{(z + 1)^2})


Correct Option: A
Explanation:

The Z-Transform of (x[n] = n) is (X(z) = \sum_{n=0}^\infty n z^{-n} = \frac{z}{(z - 1)^2}).

What is the Z-Transform of the sequence (x[n] = \sin(\omega_0 n))?

  1. (X(z) = \frac{z \sin(\omega_0)}{z^2 - 2z \cos(\omega_0) + 1})

  2. (X(z) = \frac{z \cos(\omega_0)}{z^2 - 2z \sin(\omega_0) + 1})

  3. (X(z) = \frac{z}{z^2 - 2z \cos(\omega_0) + 1})

  4. (X(z) = \frac{z}{z^2 - 2z \sin(\omega_0) + 1})


Correct Option: A
Explanation:

The Z-Transform of (x[n] = \sin(\omega_0 n)) is (X(z) = \sum_{n=0}^\infty \sin(\omega_0 n) z^{-n} = \frac{z \sin(\omega_0)}{z^2 - 2z \cos(\omega_0) + 1}).

What is the Z-Transform of the sequence (x[n] = \cos(\omega_0 n))?

  1. (X(z) = \frac{z^2 - 1}{z^2 - 2z \cos(\omega_0) + 1})

  2. (X(z) = \frac{z^2 + 1}{z^2 - 2z \cos(\omega_0) + 1})

  3. (X(z) = \frac{z}{z^2 - 2z \cos(\omega_0) + 1})

  4. (X(z) = \frac{1}{z^2 - 2z \cos(\omega_0) + 1})


Correct Option: A
Explanation:

The Z-Transform of (x[n] = \cos(\omega_0 n)) is (X(z) = \sum_{n=0}^\infty \cos(\omega_0 n) z^{-n} = \frac{z^2 - 1}{z^2 - 2z \cos(\omega_0) + 1}).

What is the Z-Transform of the sequence (x[n] = e^{\alpha n}), where (\alpha) is a constant?

  1. (X(z) = \frac{z}{z - e^{\alpha}})

  2. (X(z) = \frac{1}{z - e^{\alpha}})

  3. (X(z) = \frac{z}{z + e^{\alpha}})

  4. (X(z) = \frac{1}{z + e^{\alpha}})


Correct Option: A
Explanation:

The Z-Transform of (x[n] = e^{\alpha n}) is (X(z) = \sum_{n=0}^\infty e^{\alpha n} z^{-n} = \frac{z}{z - e^{\alpha}}).

What is the Z-Transform of the sequence (x[n] = \delta[n]), where (\delta[n]) is the unit impulse function?

  1. (X(z) = 1)

  2. (X(z) = z)

  3. (X(z) = \frac{1}{z})

  4. (X(z) = 0)


Correct Option: A
Explanation:

The Z-Transform of (x[n] = \delta[n]) is (X(z) = \sum_{n=0}^\infty \delta[n] z^{-n} = 1).

What is the Z-Transform of the sequence (x[n] = n^2)?

  1. (X(z) = \frac{z}{(z - 1)^3})

  2. (X(z) = \frac{z^2}{(z - 1)^3})

  3. (X(z) = \frac{1}{(z - 1)^3})

  4. (X(z) = \frac{z}{(z + 1)^3})


Correct Option: A
Explanation:

The Z-Transform of (x[n] = n^2) is (X(z) = \sum_{n=0}^\infty n^2 z^{-n} = \frac{z}{(z - 1)^3}).

What is the Z-Transform of the sequence (x[n] = \cos(\omega_0 n) + j \sin(\omega_0 n))?

  1. (X(z) = \frac{z(z - \cos(\omega_0))}{z^2 - 2z \cos(\omega_0) + 1})

  2. (X(z) = \frac{z(z + \cos(\omega_0))}{z^2 - 2z \cos(\omega_0) + 1})

  3. (X(z) = \frac{z}{z^2 - 2z \cos(\omega_0) + 1})

  4. (X(z) = \frac{1}{z^2 - 2z \cos(\omega_0) + 1})


Correct Option: A
Explanation:

The Z-Transform of (x[n] = \cos(\omega_0 n) + j \sin(\omega_0 n)) is (X(z) = \sum_{n=0}^\infty (\cos(\omega_0 n) + j \sin(\omega_0 n)) z^{-n} = \frac{z(z - \cos(\omega_0))}{z^2 - 2z \cos(\omega_0) + 1}).

What is the Z-Transform of the sequence (x[n] = \left{\begin{array}{ll} 1, & n = 0\ 2, & n = 1\ 3, & n = 2\ 0, & \text{otherwise} \end{array}\right.)?

  1. (X(z) = \frac{z^2 + 2z + 3}{z^3})

  2. (X(z) = \frac{z^2 - 2z + 3}{z^3})

  3. (X(z) = \frac{z^2 + 2z - 3}{z^3})

  4. (X(z) = \frac{z^2 - 2z - 3}{z^3})


Correct Option: A
Explanation:

The Z-Transform of (x[n]) is (X(z) = \sum_{n=0}^\infty x[n] z^{-n} = 1 + 2z^{-1} + 3z^{-2} = \frac{z^2 + 2z + 3}{z^3}).

What is the Z-Transform of the sequence (x[n] = \left{\begin{array}{ll} 1, & n \text{ is even}\ 0, & n \text{ is odd} \end{array}\right.)?

  1. (X(z) = \frac{1}{1 - z^{-2}})

  2. (X(z) = \frac{z}{1 - z^{-2}})

  3. (X(z) = \frac{1}{1 + z^{-2}})

  4. (X(z) = \frac{z}{1 + z^{-2}})


Correct Option: A
Explanation:

The Z-Transform of (x[n]) is (X(z) = \sum_{n=0}^\infty x[n] z^{-n} = 1 + z^{-2} + z^{-4} + \cdots = \frac{1}{1 - z^{-2}}).

What is the Z-Transform of the sequence (x[n] = n \cos(\omega_0 n))?

  1. (X(z) = \frac{z(z - \cos(\omega_0))}{(z - \cos(\omega_0))^2 + \sin^2(\omega_0)})

  2. (X(z) = \frac{z(z + \cos(\omega_0))}{(z + \cos(\omega_0))^2 + \sin^2(\omega_0)})

  3. (X(z) = \frac{z}{(z - \cos(\omega_0))^2 + \sin^2(\omega_0)})

  4. (X(z) = \frac{1}{(z - \cos(\omega_0))^2 + \sin^2(\omega_0)})


Correct Option: A
Explanation:

The Z-Transform of (x[n] = n \cos(\omega_0 n)) is (X(z) = \sum_{n=0}^\infty n \cos(\omega_0 n) z^{-n} = \frac{z(z - \cos(\omega_0))}{(z - \cos(\omega_0))^2 + \sin^2(\omega_0)}).

What is the Z-Transform of the sequence (x[n] = \left{\begin{array}{ll} 1, & n = 0\ -1, & n \text{ is odd}\ 0, & n \text{ is even and } n \ne 0 \end{array}\right.)?

  1. (X(z) = \frac{1 - z^{-1}}{1 + z^{-1}})

  2. (X(z) = \frac{1 + z^{-1}}{1 - z^{-1}})

  3. (X(z) = \frac{1}{1 + z^{-1}})

  4. (X(z) = \frac{1}{1 - z^{-1}})


Correct Option: A
Explanation:

The Z-Transform of (x[n]) is (X(z) = \sum_{n=0}^\infty x[n] z^{-n} = 1 - z^{-1} - z^{-3} - z^{-5} + \cdots = \frac{1 - z^{-1}}{1 + z^{-1}}).

What is the Z-Transform of the sequence (x[n] = \left{\begin{array}{ll} 1, & n = 0\ 2, & n = 1\ 3, & n = 2\ 4, & n = 3\ 0, & \text{otherwise} \end{array}\right.)?

  1. (X(z) = \frac{1 + 2z^{-1} + 3z^{-2} + 4z^{-3}}{1 - z^{-1}})

  2. (X(z) = \frac{1 + 2z^{-1} + 3z^{-2} + 4z^{-3}}{1 + z^{-1}})

  3. (X(z) = \frac{1 - 2z^{-1} + 3z^{-2} - 4z^{-3}}{1 - z^{-1}})

  4. (X(z) = \frac{1 - 2z^{-1} + 3z^{-2} - 4z^{-3}}{1 + z^{-1}})


Correct Option: A
Explanation:

The Z-Transform of (x[n]) is (X(z) = \sum_{n=0}^\infty x[n] z^{-n} = 1 + 2z^{-1} + 3z^{-2} + 4z^{-3} = \frac{1 + 2z^{-1} + 3z^{-2} + 4z^{-3}}{1 - z^{-1}}).

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