Principles of Analog & Digital Comm. - Dec 2013

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.

Attempt any four of the following:

1 (a) What is double spotting?(5 marks) 1 (b) Explain Eye pattern in detail(5 marks) 1 (c) Explain under water acoustic channel(5 marks) 1 (d) Explain low level modulated AM transmitter(5 marks) 1 (e) Compare FDM and TDM(5 marks) 2 (a) State and prove sampling theorem for low pass band limited signal(8 marks) 2 (b) Explain balanced modulator using FETs(6 marks) 2 (c) In an AM radio receiver the loaded Q of the antenna circuit at the input to the mixer is 100. If the intermediate frequency is 455 KHz, calculate the image frequency and its rejection at 1 MHz.(6 marks) 3 (a) Explain what is meant by quantization noise. Explain in detail.(8 marks) 3 (b) Find the mathematical expression of FM Signal(6 marks) 3 (c) Draw block diagram of BPSK generation with waveform(6 marks) 4 (a) Calculate the maximum bitrate for a channel having BW 3100 Hz and signal to noise ration 10db.(4 marks) 4 (b) State and prove the following properties of Fourier transform
(i) Time Shifting
(ii) Convolution in time domain(8 marks) 4 (c) Explain the term:
(i) Shot noise and equivalent noise temperature
(ii) Friis transmission formula(8 marks) 5 (a) Draw and explain PCM-TDM system(10 marks) 5 (b) What are the disadvantages of tune RF receiver? Draw the circuit of a superheterodyne receiver and explain the same.(10 marks) 6 (a) Draw neat block diagram of delta modulator and explain its working. What are the draw backs of delta modulator? How are they overcome by ADM?(8 marks)

Write Short notes on:

6 (b) (i) Noise Triangle(3 marks) 6 (b) (ii) Pre-emphasis and De-emphasis(3 marks) 6 (b) (iii) White noise(3 marks) 6 (b) (iv) Properties of line codes.(3 marks)