Digital Communication Quiz Questions and Answers Pdf - 1

Question: 1

An optical fibre has refractive index core

(A) Variable with refractive index increases from low at the centre to high the junction with cladding

(B) Uniform surrounded by variable index cladding

(C) Low and high refractive index cladding

(D) High and low refractive index cladding

Question: 2

In microwave communication links, the rain drop attenuation experienced is mainly due to

(A) Refraction of microwaves through liquid drop lenses formed by rain

(B) Scattering of microwaves by collection for water drops

(C) Resonance absorption of atomic vibration in water molecules

(D) Absorption of microwave energy by water vapour

Question: 3

Usually, microwave signals are not used for ionospheric propagation. The reason is

(A) Microwave penetrate through ionospheric layers

(B) Scattering prevents propagation of microwave through ionosphere

(C) Drastic dispersion takes place for microwave signals in ionosphere

(D) Ionosphere layers absorb microwaves tremendously

Question: 4

What is the maximum signal propagation time for a geosynchronous satellite transmission system?

(A) 140 ms

(B) 220 ms

(C) 280 ms

(D) 560 ms

Question: 5

The modulation scheme used in GSM is

(A) Amplitude shift keying

(B) Gaussian minimum shift keying

(C) Phase shift keying

(D) Frequency shift keying