Cochin University of Science and Techology (CUST) 2005-2nd Year B.Tech communication engineering - Question Paper

University ques. paper - May 2005.


Btech 4th semester communication engineering. (marks:100)


1. a) Draw the block diagram of a communication system & discuss.


b) Compare analog & digital communication.

OR

2. a) discuss continuous spectra & discrete spectra.

b) An amplifier operating over a frequency range of 455 to 460 KHz has a 200 Kilo
ohm input resistor. What is the rms noise voltage at the input to this amplifier
if the ambient temperature is 17 degree celsious.


3. a) discuss frequency & phase modulation.

b) In an FM system if the modulation index is doubled by halving the modulation
frequency, what will be the effect of maximum deviation?

OR

4. a) elaborate the principal features of AM & FM? discuss the frequency spectrum
of an AM wave.

b) When a broadcast AM transmitter is 50% modulated ,its antenna current is 12A.
What will be the current when the modulation depth is increased to 0.9?

5. a) discuss the working of an FM stereo transmitter with the help of a block
diagram.

b) provided the modulating signal Am SinWmt , discuss the generation of DSB-SC
waveform with the help of a block diagram & necessary mathematical relations.

OR

6. a) Draw the complete block diagram of Armstrong frequency modulatuion system
& discuss the functions of mixer & multipliers Shown.

b) describe & define independent side band transmission.

7. a) elaborate the various methods used for detection of FM signal & discuss any
1 of them? What is the importance of AGC circuit in the receiver ? discuss
the working of AGC with the help of a circuit.

OR


8. a)Use a circuit diagram to help in an explanation of how a balanced modulator is
able to demodulate SSB signals.

b) discuss the working of a super heterodyne receiver with a block diagram.

9. a) discuss the elemental phone setup with the help of a diagram.Write short notes
of cross bar switch & DTMF dialing.


OR

10. a) discuss various kinds of signaling.

b) discuss a basic analog switching system.


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Earning:   Approval pending.