(a) Humans can hear sounds containing frequency components between 20 Hz and 20 kHz. What is the maximum sampling interval, T, that can be used to sample a signal without loss of audible information? (b) An signal is described by the expression analogue x(t)=sin(480лt) + 3sin(720лt). (i) Determine the Nyquist sampling rate for x(t). (ii) Find x[n], obtained by sampling x (t) at 600 Hz. (iii) Describe the reconstructed signal y(t) if x[n] is passed through an ideal digital-to-analogue (D/A) converter. (iv) Has aliasing occurred? (c) What are the characteristics of a filter that could be used for signal recovery/reconstruction in this example? (4) (3) (3) (3) (2) (2)