ANALOG COMMUNICATION (utu question paper)

ANALOG COMMUNICATION

SEM.IV, 2012
B.TECH
UTTARAKHAND TECHNICAL UNIVERSITY
(UTU)

Time: 3 Hours

Total Marks: 100

Note: Attempt all questions. Each question carries equal marks

Attempt any four parts of the following:

1. Explain frequency division multiplexing and time division multiplexing, also compares them.
2. What do you understand by Hilbert transform and inverse Hilbert transform? Write properties and application of Hilbert transform.
3. Describe Quadrature Amplitude Modulation. Give its application?
4. Explain following
   (i) Modulation index
   (ii) Envelope detector
   (iii) Baseband and passband signals
   (iv) Signal power
5. Draw the circuit of balanced modulator using  FETs. Explain its operation in mode 1 and mode 2.
6. Explain square law diode modulation method for AM generation. In an AM system, the modulating signal is sinusoidal with frequency f Hz. If 70%  modulation is used, then find the ratio of total sideband power in the modulation signal to the total power in the modulation signal to the total power.

Attempt any four parts of the following:

1. What is angel modulation? Explain different types of angle modulation with mathematical expression.
2. Explain the relationship between phase modulation and frequency modulation.
3. Draw the circuit diagram of varactor diode modulator and explain its working.
4. Explain Armstrong method for the generation of wideband FM.
5. Write comparison between narrow band FM and wide band FM.
6. Explain the working of a balanced frequency discriminator with the help of circuit diagram.

Attempt any two parts of the following:

1. Draw the block diagram of communication system, explain each block in detail. What is the fundamental limitation of communication system?
2. Explain methods of SSB generation. Write its advantage with respect to DSB-SC?
3. Explain single tone amplitude modulation with mathematical expression? Define power contain in AM wave?

Attempt any two parts of the following:

1. What are the types of pulse modulation system, explain PAM, PWM, PPM with its transmitter and receiver section?
2. State and prove the sampling theorem and also explain natural sampling and flat top sampling with the help of suitable diagram?
3. Explain pulse code modulation system with its respective block diagram and derive the relationship for transmission bandwidth in a PCM system?

Attempt any two parts of the following:

1. What are the different types of noise associated with communication system explain each in detail?
2. Explain noise sources and derive the expression for voltage and current models of a noisy resistor?
3. Calculate following:
   (i) Equivalent noise bandwidth in communication system
   (ii) Signal to noise ratio
   (iii) Noise figure

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