MATLAB Signal Processing 3

Question 1

What does the MATLAB `fftshift(X)` function do to the output of `fft`?

Accepted Answer

Shifts the zero-frequency component to the center of the spectrum

Answer

`fftshift` rearranges the FFT output so that the zero-frequency (DC) component is centered, making two-sided spectra easier to visualize.

Question 2

Which MATLAB window function call produces a Hamming window of length N?

Accepted Answer

hamming(N)

Answer

`hamming(N)` returns an N-point Hamming window, a raised cosine with coefficients that minimize the maximum sidelobe level.

Question 3

What does the MATLAB `hilbert(x)` function return?

Accepted Answer

The analytic signal of x, with the original signal as real part and its Hilbert transform as imaginary part

Answer

`hilbert(x)` returns the analytic signal, where the real part is x and the imaginary part is the Hilbert transform of x, useful for computing the envelope.

Question 4

Which MATLAB function designs a Chebyshev Type I IIR lowpass filter with ripple Rp dB in the passband?

Accepted Answer

cheby1(n, Rp, Wn)

Answer

`cheby1(n, Rp, Wn)` designs a Chebyshev Type I filter that has equiripple in the passband and a monotonic stopband response.

Question 5

Why is `filtfilt(b, a, x)` preferred over `filter(b, a, x)` in many signal processing applications?

Accepted Answer

It achieves zero-phase distortion by filtering the signal forward and backward

Answer

`filtfilt` applies the filter twice — once forward and once backward — so phase shifts cancel out, yielding zero phase delay.

MATLAB - MATLAB Technical Computing Practice Test

MATLAB - MATLAB Technical Computing Practice Test

MATLAB Signal Processing 3