The sequences x[n] = {3, −2, −3, 3} and h[n] = {4, −3} both start at n = 0. Find the sample y[2] of the convolution y[n] = x[n] ∗ h[n].
Convolution & LTI systems worksheet with answers
1.Easy
x[n] = {3, −2, −3, 3}, n = 0…3h[n] = {4, −3}, n = 0…1
y[2] =
2.Easy
The sequences x[n] = {2, 4, −2} and h[n] = {4, −1} both start at n = 0. Find the sample y[1] of the convolution y[n] = x[n] ∗ h[n].
x[n] = {2, 4, −2}, n = 0…2h[n] = {4, −1}, n = 0…1
y[1] =
3.Medium
A system has the impulse response h(t) = e−1tu(t). The input is a step x(t) = 1·u(t). Find the output y(0.5) at t = 0.5 s.
h(t) = e−1tu(t)x(t) = 1·u(t)t = 0.5 s
y(0.5) =
4.Medium
A system has the impulse response h(t) = e−2tu(t). The input is a step x(t) = 2·u(t). Find the output y(1) at t = 1 s.
h(t) = e−2tu(t)x(t) = 2·u(t)t = 1 s
y(1) =
5.Hard
A system obeys y[n] = 0.6·y[n − 1] + 2·x[n] and starts at rest. Find its impulse response sample h[4].
y[n] = 0.6y[n − 1] + 2x[n]x[n] = δ[n]
h[4] =
6.Hard
A pulse train has height 1, pulse width 1.25 ms and period 5 ms. Find the amplitude c1 of harmonic number 1, at 200 Hz.
A = 1τ = 1.25 msT = 5 ms
c1 =
Answer key
- 1. y[2] = −6
- 2. y[1] = 14
- 3. y(0.5) = 0.3935
- 4. y(1) = 0.8647
- 5. h[4] = 0.2592
- 6. c1 = 0.4502
Full step-by-step solutions: practise this topic on examproblems.com.