1(a)
What is the effect of Gaussian noise on digital communication?

5 M

1(b)
A 4kHz bandlimited signal is sampled at Nyquist rate and quantized to 4 levels Q1, Q2, Q3, Q4. The respective probabilities are P

_{1}=P_{2}=1/8 and P_{3}=P_{4}=3/8. Find the rate of information.
5 M

1(c)
Prove time convolution property of Fourier transform.

5 M

1(d)
Explain Electronic Communication System with block diagram.

5 M

2(a)
Draw circuit diagram of Foster Seeley discriminator and explain its working with phasor diagram.

10 M

2(b)
Explain overload and hunting error in Delta Modulation. Find the condition to avoid slope overload error.

10 M

3(a)
Draw the circuit diagram for ring modulator for generating DSB-SC AM signal and explain its working.

10 M

3(b)
Explain the working of envelope detector. An audio signal of bandwidth 5 kHz is modulated on carrier frequency 1MHz using conventional AM. Determine range of values of RC for successful demodulation of this signal using an envelope detector.

10 M

4(a)
What is multiplexing in communication systems? Draw the block diagram of frequency division multiplexing to transmit five signals.

10 M

4(b)
A carrier C(t)=Acos 2?t is angle modulated(PM or FM) by a sinusoidal signal m(t)=2cos2000?t. The deviation constants are k

i. Determine modulation index in each case

ii. Determine the bandwidth in each case using Carson's rule

iii. If amplitude of m(t) is decreased by a factor of two, how would bandwidth change.

_{p}=1.5 rad/V and k_{f}= 3000 Hz/V.i. Determine modulation index in each case

ii. Determine the bandwidth in each case using Carson's rule

iii. If amplitude of m(t) is decreased by a factor of two, how would bandwidth change.

10 M

5(a)
Explain the concept of image frequency and its rejection. Discuss double spotting.

10 M

5(b)
Prove sampling theorem for low pass signals. What is use of anti-aliasing filter?

10 M

6(a)
Draw the ASK, PSK and FSK waveforms for digital data 10100110.

10 M

6(b)
What is need of pre-emphasis and de-emphasis in FM? Explain the standards used for the same with circuits.

10 M

7(a)
Define Noise factor and Noise temperature.

5 M

7(b)
Compare TDM and FDM.

5 M

7(c)
Explain Friss Transmission formula.

5 M

7(d)
Discuss Third Method of SSB generation

5 M

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