(a)[4]
Suggest four benefits of optic fibres over coaxial cables for data transmission.
(b(i))[1]
State the region of the electromagnetic spectrum where radiation with wavelength $1310\,\text{nm}$ lies.
(b(ii))[1]
Suggest why this radiation is chosen instead of visible light.
(c(i))[2]
An optic fibre has an attenuation per unit length of $0.2\,\text{dB km}^{-1}$. A signal is sent along an optic fibre of length $30\,\text{km}$ to a receiver. The noise power at the receiver is $9.3\,\mu\text{W}$. The least acceptable signal-to-noise ratio at the receiver is $26\,\text{dB}$. Calculate the minimum signal power at the receiver.
(c(ii))[2]
Calculate the minimum input signal power to the optic fibre.