The transmission of signals using optic fibres has, to a great extent, replaced the use of coaxial cables. Advantages of optic fibres include greater bandwidth and very little crosslinking.
Suggest an advantage of greater bandwidth.
State what is meant by crosslinking.
In telecommunications, a signal power of 
is used as a reference power. Signal powers relative to this reference power and expressed in 
are said to be measured in ‘
’. Show that a signal power of 
is equivalent to 
.
A signal of input power is transmitted along an optic fibre for an uninterrupted distance of 
. The optic fibre has an attenuation per unit length of 
. Calculate the output power 
from the optic fibre.
.
