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

1(a)
Compare analog and digital communication system.

5 M

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

5 M

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

5 M

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

5 M

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

5 M

2(a)
Explain the term thermal noise. Prove that the noise voltage \( V_{n}\sqrt{4kTBR} \)/ 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.

1. Thermaol noise power in dBm. 2. RMS noise volatage for a 100Ω internal resistance and a 100Ω load resistance.

10 M

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

10 M

3(a)
An AM signal appears across a 50Ω load and has the following equation \[v(t)= 12(1+sin12.566×10

ii) Calculate modulation index, sideband frequencies, total power and bandwidth.

^{3}t) sin 18.85×10^{6}t volts br> i) Sketch the envelope of this signal in time domain.ii) Calculate modulation index, sideband frequencies, total power and bandwidth.

10 M

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

10 M

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

10 M

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

10 M

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

10 M

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

10 M

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

10 M

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

10 M

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