Analog and Digital Communication — Summer 2024

Explain Elements of communication system with diagram.

Explain Need of Modulation in details.

State Friss Formula for overall Noise Factor of amplifiers in cascade and Using Friss Formula, Find Overall Noise Figure of three stage cascaded amplifier, each stage having a power gain of 10 dB and noise figure of 5 dB.

What do you mean by VSB Modulation and Why it is used?

Explain various forms of External noise in brief.

Derive mathematical representation of AM and Explain signification of Modulation Index with necessary waveforms.

Discuss Noise factor. Derive expression for noise factor of amplifier connected in cascade.

For FM System, the modulating frequency is 10 KHz and maximum deviation is 75 KHz Calculate bandwidth of system using Carson’s Rule.

Give comparison of wideband and narrowband FM.

Explain Armstrong method of FM generation with neat diagram.

The antenna current of an AM transmitter is 8 Afor an unmodulated carrier but it increases to 8.93 Awhen the carrier is modulated by a single sine wave. Find the percentage modulation. Determine the antenna current when the percentage modulation changes to 0.8.

Derive the formula for the instantaneous value of an FM voltage and define the modulation index. And draw the waveforms of information signal and its FM modulated signal.

Explain the importance of Pre-emphasis and De-emphasis circuits in FM. Sketch a typical Pre-emphasis and De-emphasis circuit.

Describe pulse width modulation. With neat sketch explain generation of PWM.

Write a short note on Full carriers AM transmitters.

For a receiver with IF and RF frequency of 455 KHz & 950 KHz respectively determine: (i) local oscillator frequency (ii) image frequency (iii) image frequency rejection ratio. take Q=70.1

Write short note on latest trends in digital communication.

Explain Pulse Code Modulation with necessary waveforms.

For Binary data: 1110100110110101 draw ASK, FSK and PSK waveform. (Assume suitable data).

Explain FSK demodulation.

State the Advantages and Application of Spread Spectrum Communication.

Draw the block diagram of Tuned Radio Frequency (TRF) Receiver and explain its operation. Describe the problems in TRF receiver.

Explain ASK demodulation.

Give comparison of wideband and narrowband FM.

Explain working principle of delta modulation with help of block diagram. What are the problems associated with delta modulation?