Question Paper: Communication System Question Paper - May 2015 - Instrumentation Engineering (Semester 4) - Mumbai University (MU)
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## Communication System - May 2015

### MU Instrumentation Engineering (Semester 4)

Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

### Attempt any five:

1 (a) Discuss the need of modulation is communication systems. 4 marks

1 (b) Write note on RF telemetry. 4 marks

1 (c) Derive Friis formula for total noise figure of cascaded amplifier. 4 marks

1 (d) Why SSB is not preferred for transmission of good quality of signal? 4 marks

1 (e) Write note on OSI reference model. 4 marks

1 (f) Compare TDM and FDM. 4 marks

2 (a) Derive an expression for an AM signal. Also derive the power relationship. 4 marks

2 (b) A 20 MHz carrier is modulated by 600Hz audio sine wave. If the carrier voltage is 5V and maximum deviation is 15 KHz. Write the equation for this frequency modulated wave. If the modulating frequency is now changed to 1.5 KHz and carrier voltage is changed to 10V, all else remaining constant, write the equation for this wave, calculate the power dissipated across 100Ω resistor by both F.M. waves. 4 marks

3 (a) Explain Indirect method of FM Generation. 4 marks

3 (b) Explain any one method of amplitude demodulation in detail. 4 marks

### Explain briefly:

4 (a) (i) Phase shift keying (PSK). 4 marks

4 (a) (ii) Binary phase shift keying (BPSK). 4 marks

4 (b) Explain PCM transmitter and Receiver system. 4 marks

### Explain briefly:

5 (a) (i) Pulse width modulation. 4 marks

5 (a) (ii) Pulse position modulation. 4 marks

### Explain briefly:

5 (b) (i) Frequency shift keying. 4 marks

5 (b) (ii) Amplitude shift keying. 4 marks

6 (a) With the help of neat sketches voltage, current and position telemetry systems. 4 marks

6 (b) Explain the various communication modes as simplex, half duplex; duplex in detail. 4 marks

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