An Audio Signal s(t) generated by a loud speaker is reflected at two different walls with reflection coefficients r1 and r2. The signal x(t) recorded by a microphone to the loud speaker, after sampling is
x(n) = s(n) +r1s(n-k1) + r2s(n-k2)
where k1 and k2 are delays of the two echoes.
a) Determine Auto correlation rxx(l) for signal x(n)
b) can we obtain r1, r2, k1, k2 by observing rxx(l)
c) what happens if r2=0.