Question Paper: Principles of Analog & Digital Comm. Question Paper - May 2017 - Information Technology (Semester 3) - Mumbai University (MU)
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## Principles of Analog & Digital Comm. - May 2017

### MU Information Technology (Semester 3)

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

### Solve any four question from Q.1(a, b, c, d, e)

1(a) Compare analog and digital communication system. 5 marks

1(b) Define modulation. Explain and Justify any two need of modulation. 5 marks

1(c) Explain in brief Pre-emphasis and De-emphasis in FM. 5 marks

1(d) Explain in brief the process of quantization. 5 marks

1(e) What is line coding. Draw the NRZ and Manchester signal for the following binary signal 10111010. 5 marks

2(a) Explain the term thermal noise. Prove that the noise voltage Vn√4kTBRVn4kTBR V_{n}\sqrt{4kTBR} / For electronic device operating at a temperature of 17°C with a bandwidth of 10 KHz, determine
1. Thermaol noise power in dBm. 2. RMS noise volatage for a 100Ω internal resistance and a 100Ω load resistance.
5 marks

2(b) State and prove time scaling property of Fourier transd 01m. Determine the Fourier transform for a rectangular pulse of amplitude 'A' and time period 'T' is from-T/2 to T/2 5 marks

3(a) An AM signal appears across a 50Ω load and has the following equation [v(t)= 12(1+sin12.566×103t) sin 18.85×106t volts br> i) Sketch the envelope of this signal in time domain.
ii) Calculate modulation index, sideband frequencies, total power and bandwidth.
5 marks

3(b) What are the limitations of 'TRF' receiver. Explain how these limitations are avoided using super heterodyne receiver. 5 marks

4(a) With the help of neat circuit diagram explain the working of Ratio detector. 5 marks

4(b) What is multiplexing in communication system. Draw and explain in brief the transmitter and receiver of FDM. 5 marks

5(a) State and prove sampling theorem for how pass band limited signal. Explain aliasing error. 5 marks

5(b) What are the various pulse modulation techniques? Explain how PPM is obtained from PWM. 5 marks

6(a) Explain in brief the generation and detection of Delta modulation. 5 marks

6(b) Explain the generation and detection of ASK signal with block diagram and waveforms. 5 marks

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