problem 1: State with reasons whether the given statements are true or false:

a) Parallel communication system is favored for video signal transmission.

b) Adding redundant bit in a transmitted signal makes sure error free communication.

c) Characteristic impedance of a transmission line based on its geometry.

d) Bandwidth of frequency modulated (FM) signal is narrower than that of amplitude modulated (AM) signal.

e) In telephony, pulse tone dialing is more proficient than Dual Tone Multi-frequency (DTMF) dialing.

f) Double spotting consequence is not observed in the case of TRF receivers.

g) Schottky barrier diode can work at higher frequency than the p-n junction diode.

h) Quantum efficiency of a photo detector doesn’t depend on the wavelength of the radiation being detected.

i) Instruction written in Assembly Language can be directly executed by the computer processor.

j) P2P networking facilitates the collaborative computation projects.

problem 2:

a) State and prove with the help of suitable diagram the sampling theorem.

b) A computer key board has 108 keys. Supposing equal probability of any key pressing compute the information content, I, carried by each key. Prove that this information is more than the information taken by the keys on the key pad of a touch tone telephone.

problem 3:

a) For a metallic conductor with ν = 10¹² collisions per second the skin depth at ω = 2π x 10¹⁰ rad frequency is 4.0 µm. Compute the plasma frequency of this conductor.

b) Compare the two wire transmission line with coaxial cable on the basis of operating frequency, losses and cost.

problem 4:

a) Describe the distortions encountered in case of amplitude modulated signal. Which of such can be removed in amplitude shift keying? How?

b) Describe the process of obtaining pulse position modulated signal from pulse amplitude modulated signal.

problem 5:

a) Design a TDM system to interlace three PAM audio signals.

b) Describe with an illustration the working of time division switching in telephony.

problem 6:

a) Describe the working of automatic gain control circuit in an AM receiver.

b) With the help of a suitable diagram describe the process of collecting the image information in serial form from a charge coupled device.

problem 7:

a) Describe different kinds of microwave horn antennae on the basis of their construction, directivity and applications.

b) Compare the various kinds of optical fibers on the basis of their construction. Describe how the modal dispersion is avoided in case of graded index fiber.

problem 8:

a) Trace the evolution of computers from micro to super computers.

b) Describe the Ethernet and Token Ring LAN protocols. How is data collision avoided in case of token ring protocol?

problem 9:

a) Describe the merits and demerits of different datagram switching methods.

b) What do you mean by the term WAP? What are the challenges faced in designing the WAP applications?