Problem 6 [25 points] What does aliasing sound like? Load the file P673.mat from the Canvas. This is a speech signal (a single sentence) sampled at 24000 samples/s. a. [5 points]

Listen to the signal using Describe what you hear. b. [5 points] Plot the one-sided magnitude spectrum from 0 to 8 kHz using N-length (X)/3; F=linspace (0,8000,N); FX=abs(fft (X)); plot (F,FX(1:N)) c. [5 points] Repeat (a) and (b) after reducing the sampling rate to 6000 samples/s. Do this by keeping only every fourth sample and discarding the other three samples. Use Y=X(1:4:end); soundsc (Y,6000) Describe what you hear. It should sound different. d. [5 points] Plot the one-sided magnitude spectrum of the signal in (c) from 0 to 3 kHz using Nl-length (Y)/2; Fl=linspace (0,3000, N1); FY=4*abs (fft (Y)); plot (F1,FY(1:N1)) e. [5 points] Compare (note differences) answers to (a) and (c), and to (b) and (d).