(a)[2]
Suggest two advantages of sending a signal in digital form instead of in analogue form.
(b)[2]
State what the parallel-to-serial converter does.
(c)[3]
In one telephone system, the sampling frequency is $8\,\text{kHz}$. During the manufacture of a compact disc, the sampling frequency is about $44\,\text{kHz}$. Suggest and explain why the sampling frequency is much higher for the compact disc.