Mumbai University Previous year question papers
IV Sem ETC-Examination June 2007
Principles of Communication
N.B.(1) Question No.1 is compulsory.
(2) . Solve any four from remaining questions.
(3) Assuri1e suitable data, if required.
1. Answer any four :-
(i) Noise Factor (ii) Noise Figure.
(b) Compare Low level and high level Modulation.
(c) With the help of diagram explain quantization.
(d)’ What is tracking error ? Explain three point tracking in Am radio receiver.
(e) ~ExplainFM noise triangle.
2. (a) Classify and explain different types of noise affecting communication.
(b) State advantages of SSB over DSB. Explain phase shift method to generate SSB AM.
3. (a) An audio frequency signal10sin 27tx 500 t is used to amplitude modulate a carrier of 50 sin 27t x 105 t Calculate:
(i) Modulation. index
(ii) Sideband frequencies
(iii) Amplitude of each sideband frequ~ncies
(iv) Bandwidth required’
(v) Total power delivered to the load of 600 Q.
(b) With a neat circuit diagram, explain varactor diode FM modulator.
4. (a) If a FM wave is represented by the equation:
V=10 sin ( 8 x 108 + 4 sin 1000 t). 10
(i) Carrier frequency’
(ii) Modulating freque:ncy
(iii) Modulation index:
(iv) Maximum deviation
(b) Explain the following with reference to radio receivers:
(iv) Double spotting.
5. (a) State and prove sampling theorem. ..
(b) Explain generation and demodulation of PPM signal with the help of suitable diagram.
6. (a) Draw differential pulse code modulation block diagram and explain its operation.
(b) With the help of neat block diagram explain the working of adaptive delta modulation.
7. (a) Write notes on
(a) TOM ~nd. FDM.
( b) Explain ISB with neat block diagram.