Principles of Analog & Digital Comm. - Dec 2015
Information Technology (Semester 3)
TOTAL MARKS: 80
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks.
Solve any four:
1 (a) Explain pre-emphasis and De-emphasis.(5 marks)
1 (b) Explain the following (i) Shot noise, (ii) Equivalent Noise temperature.(5 marks)
1 (c) A single tone FM single is given by VFM (t)=10 sin (16 π×106 t+20 sin 2 π × 103 t)
i) Maximum frequency deviation
ii) BW of FM by using Carson's rule.(5 marks) 1 (d) What are the drawbacks in DM system and how these drawbacks can overcome.(5 marks) 1 (e) Explain the need for modulation.(5 marks) 2 (a) Explain the basic principle, working of Transmitter and receiver and BPSK. Also draw the BPSK Waveform for the following binary signal 10110110.(10 marks) 2 (b) Draw the data formats (linecode) of any five for the given binary 10101101.(10 marks) 3 (a) Explain PWM generation and degeneration method.(10 marks) 3 (b) Describe PCM and also explain the PCM encoder and decoder with block diagram.(10 marks) 4 (a) Explain Foster Seeley discriminator and Compare the performance of Foster Seeley and Ratio detector.(10 marks) 4 (b) A sinusoidal carrier has an amplitude of 20v and a frequency of 200kHz. It is amplitude modulated by a sinusoidal voltage of amplitude 6v and frequency 1 kHz. Modulated voltage is developed across a 80Ω resistance.
i) Write the equation for the modulated wave.
ii) Determine the modulation index.
iii) Draw the spectrum of modulated wave.
iv) Calculate the total average power.(10 marks) 5 (a) Explain the generation and demodulation of SSBSC.(10 marks) 5 (b) State and prove the following properties of Fourier Traulform.
i) Time Shifting.
ii) Differentiation in Time domain.(10 marks)
Answer any four:
6 (a) QPSK(5 marks) 6 (b) PCM-TDM(5 marks) 6 (c) Friss formula(5 marks) 6 (d) Image frequency and its rejection(5 marks) 6 (e) Sampling theorem.(5 marks)