Electronics (ECE) - MCQ Practice Questions

A discrete signal x[n] = {1, 2, 3, 2} has a length of 4 samples. What is the 4-point DFT at k=0?

A signal x(t) is time-limited to 0 to T seconds. What is the minimum sampling rate required to avoid aliasing if its bandwidth is B Hz?

An LTI system has impulse response h(t) = e^(-3t)u(t). Is this system stable?

The output of a system is y[n] = 0.5y[n-1] + x[n]. What is the transfer function H(z)?

A sinusoidal signal x(t) = 5sin(2πf₀t + π/4) is sampled at fs = 10f₀. What is the Nyquist frequency?

Which window function provides the narrowest main lobe but highest side lobes in frequency domain?

For a sequence x[n] = {1, 2, 1, -1}, what is the circular convolution with itself using 4-point DFT?

A signal has autocorrelation R_x(τ) = Ae^(-2|τ|). What is its bandwidth (3dB) approximately?

A filter has poles at z = 0.7 and z = 0.9. What can we infer about its stability and response?

An analog filter has magnitude response |H(jω)| = 1/√(1+(ω/ωc)⁴). What is the order of the filter?

A real discrete signal x[n] has DTFT X(e^jω). What is the relationship between X(e^jω) and X(e^-jω)?

A linear phase FIR filter of length N has which characteristic for group delay?

A speech signal is band-limited to 4 kHz and sampled at 8 kHz. If 1000 samples are collected, what is the frequency resolution of its DFT?

A system with H(s) = (s+2)/((s+1)(s+3)) is analyzed. What is the steady-state response to u(t) = 10sin(2t)?

In multirate signal processing, if a signal is decimated by factor M and then interpolated by factor M, what is the output relationship to input?

A minimum-phase system has a zero at z = 2. Where should its mirror zero be placed for a linear-phase equivalent system?

A signal undergoes spectral analysis using FFT with windowing. If spectral leakage is observed, which of the following is NOT a solution?

A continuous-time signal x(t) = 5cos(2π×100t) is sampled at 250 Hz. What is the Nyquist frequency required?

For a causal LTI system with transfer function H(z) = 1/(1-0.5z^-1), the system is:

The energy of a discrete-time signal x[n] = (0.5)^n u[n] is: