(a(i))[1]
State what attenuation means.
(a(ii))[2]
State what noise means.
(b)[1]
Using (a)(ii) as your reference, explain why transmitting the signal in digital form has an advantage over analogue form.
(c)
Fig. 4.1 shows a section of an analogue signal.
(c(i))[1]
For the digital number at time $t = 3.0\text{ ms}$, show the least significant bit (LSB) by underlining it.
(c(ii))[2]
State the digital numbers that correspond to the sampling times from time $t = 4.0\text{ ms}$ to time $t = 6.0\text{ ms}$.
(d)[3]
The digital signal sent is changed back into an analogue signal by a digital-to-analogue converter (DAC). On Fig. 4.3, show how the DAC output level varies with time $t$ from $t = 0$ to $t = 4.0\text{ ms}$. Assume that transmission delay along the line is negligible.