Which of the following four alternatives is not correct?
a) to increase the sensitivity
b) to reduce the time lag between transmission and reception of the information signal
c) to reduce the size of antenna
d) to reduce the fractional band width, that is the ratio of the signal band width to the centre frequency
Consider telecommunication through optical fibres. Which of the following statements is not true?
a) Optical fibres can be graded refractive index
b) Optical fibres are subjected to electromagnetic interference from outside
c) Optical fibres have extremely low transmission loss
d) Optical fibres may have homogeneous core with a suitable cladding