Electronics (ECE) - MCQ Practice Questions

The Z-transform of x[n] = ($\frac{1}{2}$)^n u[n] is:

An even signal x(t) has Fourier transform X(f). What can be said about X(f)?

The energy of a signal x[n] = {1, 2, -1, 0} is:

A discrete signal x[n] = cos(π n/6) has a period of:

Which of the following is NOT a property of the Laplace transform?

A signal x(t) is band-limited to 1 kHz. Using Nyquist theorem, the minimum sampling rate should be:

For a linear time-invariant system, if input x₁(t) produces y₁(t) and x₂(t) produces y₂(t), then input ax₁(t) + bx₂(t) produces:

The region of convergence (ROC) of the Z-transform of x[n] = a^n u[n] is:

A moving average filter y[n] = (x[n] + x[n-1])/2 has a zero at:

A signal has autocorrelation R(0) = 10 and R(1) = 5. What is the signal's power?

A low-pass filter has magnitude response |H(jω)| = 1/(√(1 + (ω/ωc)²)). At ω = ωc, the magnitude is:

A second-order system has poles at s = -1 ± j2. Its natural frequency ωn is:

A causal stable filter has H(s) = (s+3)/((s+1)(s+2)). Using partial fractions, the impulse response contains:

A 1024-point FFT is computed on a signal. The frequency resolution is 0.1 Hz. What is the sampling frequency?

A continuous-time signal x(t) = 5cos(2π × 500t) + 3sin(2π × 1500t) is sampled at 4 kHz. What is the Nyquist frequency for this signal, and will aliasing occur?

The Z-transform of a discrete-time signal is X(z) = z/(z-0.5) with ROC |z| > 0.5. The corresponding time-domain signal is:

A first-order low-pass filter has transfer function H(s) = ωc/(s + ωc). At what frequency (in terms of ωc) does the magnitude response drop to 1/√2 of its DC value?

A causal discrete-time LTI system has impulse response h[n] = (0.8)^n × u[n]. If the input is x[n] = δ[n] - 0.5×δ[n-1], find y[0] + y[1]:

For a linear time-invariant system with Laplace transform H(s) = 1/(s+2), determine the response to input x(t) = e^(-2t)×u(t):

A signal's autocorrelation function is R(τ) = 10 + 8cos(2π×100τ). What is the average power of the signal?