The noise in an electrical circuit can depend on the nature of the coupling mechanism. In particular, the following types of coupling are available:
(a) Conductive coupling
(b) Inductive coupling
(c) Capacitive coupling
(d) Optical coupling
Compare these four types of coupling with respect to the nature and level of noise that is fed through or eliminated in each case.
Discuss ways to reduce noise that is fed through in each type of coupling.
The noise due to variations in ambient light can be a major problem in optically coupled systems. Briefly discuss a method that could be used in an optically-coupled device in order to make the device immune to variations in the ambient light level.