Mumbai University Previous year question papers
IV Sem Electronics Examination Dec 2009
Basic of Analog & Digital Communication System
N.S.: (1) Question NO.1 is compulsory.
(2) Attempt any four questions from the remaining six questions.
(3) Figures to the right indicate full marks for the question. ‘2–~
(4) Assume suitable data whenever necessary.
1. Attempt any four of the following :-
(a) Derive an expression for an A.M.signal
(b) Compare A.M.and EM.
(c) Write a note on EM. noise triangle
(d) Write a note on VSB transmission
(e) ExplainTime Divisionmultiplexing.
2. (a) Compare the followingamplitude modulated systems :- 12
DSB-FC, DSB-SC, SSB, ISB, VSB.
(b) Drawthe block diagram of high level A.M.transmitter and explain in detail. 8
3. (a) Define:-
(i) Signal to Noise Ratio
(ii) Noise Factor
(iii) Noise Figure
(b) Explain Armstrong method of EM. generation with the help of a neat block diagram and phaser diagram.
4. (a) With the help of neat block diagram and waveforms explain superheterodyne A.M. radio receiver.
(b) Explain the working of a phase descriminator EM. detector with the help of neat circuit diagram and wave.
5. (a) Explain the following in relatiOnto propagation of radio waves :-
(i) Virtual height
(ii) Maximum usable frequency
(iii) Skip distance
(v) Critical frequency.
(b) Draw the block diagram of PCM system and exp~ain each block in detail. Also draw the waveforms.
6. (a) Explain with the help of waveforms P.A.M., P.W.M.and P.P.M.generation and detection.
(b) Explainadaptivedelta modulation.Howdoes it overcomeslope overloaderror? Which error it increases?
7. Write a notes on :-
(a) Companding Curve
(b) Frequency Division Multiplexing
(c) Collector Modulator.