CS2204 ANALOG AND DIGITAL COMMUNICATION ANNA UNIVERSITY QUESTION PAPER NOV/DEC 2009 for CSE & IT dpt's...
Posted by R.Anirudhan
B.E./B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2009
Computer Science and Engineering
CS 2204 — ANALOG AND DIGITAL COMMUNICATION
Time : Three hours Maximum : 100 Marks
Answer ALL Questions.
PART A — (10 × 2 = 20 Marks)1. Draw the waveforms of AM signal and DSB-SC signal.
2. What is the required bandwidth for FM signal, in terms of frequency
3. Draw the phasor diagram of QPSK.
4. Define information capacity and bit rate.
5. Draw PWM and PPM waveforms.
6. Draw the Eye pattern and indicate how ISI is measured from it.
7. Compare the merits and demerits of error detection and correction.
8. Give typical CRC-16 generating circuit.
9. Define effective jamming power and processing.
10. What is the principle of frequency hopping spread spectrum?
PART B — (5 × 16 = 80 Marks)
11. (a) Derive expression for AM wave. Define modulation index and express itsvalue in terms of maximum and minimum voltage values of signal. Draw
the spectrum and time-domain signal of AM wave.
(b) Define FM and PM modulation. Write down their equations. Describe
suitable mechanism that can produce PM from FM modulator.
12. (a) Draw the block diagram of FSK receiver and explain the operation.
Determine the : (i) peak frequency deviation (ii) minimum bandwidth
(iii) baud for FSK signal with a mark frequency of 49 kHz, space
frequency of 51 kHz, and input bit rate of 2 kbps.
(b) Draw the block diagram of QPSK modulator and explain its operation.
For QPSK modulator, construct the truth table, phasor diagram and
13. (a) What is companding? Explain analog companding process with the help
of block diagram.
(b) How does delta modulation differ from PCM? Explain delta modulation
transmitter with the help of a block diagram.
14. (a) Explain the difference between error detection and error correction.
Determine the BCS for the following data and CRC generating
Data 0 1 2 4 5 7 ) ( x x x x x x x G + + + + + =
CRC 0 1 4 5 ) ( x x x x x P + + + = .
(b) Discuss UART transmitter and receiver in detail. Under what conditions,
asynchronous mode of data transfer is better?
15. (a) With the help of block diagram explain how DSSS can be implemented.
Draw the input and output waveforms.
(b) Explain the frequency – hopped spread spectrum with a block diagram.
How PN sequences are generated?