(a(i))[1]
State the meaning of a digital signal.
(a(ii))[2]
State the component names for X and Y on Fig. 3.1.
(a(iii))[2]
Describe what the ADC does.
(b(i))[2]
An optic fibre has a length of $84\,\text{km}$, and its attenuation per unit length is $0.19\,\text{dB km}^{-1}$. The input power to the optic fibre is $9.7\,\text{mW}$. The signal-to-noise ratio at the output from the optic fibre is $28\,\text{dB}$. Calculate, in dB, the ratio $\frac{\text{input power to optic fibre}}{\text{noise power at output of optic fibre}}$.
(b(ii))[3]
Calculate the noise power at the fibre output.