Saturday, July 14, 2012

TAMILNADU TANCA 2012 M.E. / M.Tech. / M.Arch. / M.Plan. Degree Programmes COMMON ADMISSIONS

M.E. / M.Tech. / M.Arch. / M.Plan. Degree Programmes
ANNA UNIVERSITY, CHENNAI 600 025

For registration   Clickhere

ELECTRICAL ENGINEERING EC2201 NOV/DEC 2010 QUESTION PAPER

B.E./B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2010
Third Semester
Electronics and Communication Engineering
EC 2201 — ELECTRICAL ENGINEERING
(Regulation 2008)
Time : Three hours Maximum : 100 Marks
PART A — (10 × 2 = 20 Marks)

1. What is a dc compound generator?
2. What is the need for starter in dc motor?
3. Why is the core of transformer laminated?
4. Define voltage regulation of a transformer.
5. What are the types of 3-ph induction motors?
6. Name the starting methods for cage motors.
7. Why should an alternator run always at synchronous speed?
8. Write down the emf equation of alternator.
9. What are the various stages of an electric power system?
10. Mention the disadvantages of HVDC transmission.

PART B — (5 × 16 = 80 Marks)

11. (a) (i) Briefly explain the construction of a DC machine with neat diagram. (Marks 10)
(ii) A dc shunt generator has a terminal voltage of 160 V and a no-load induced emf of 168 V. The resistances of armature and field are 0.03 and 20 . Find the armature current, field current and load current. Neglect armature reaction. (Marks 6)
Or
(b) (i) Explain the characteristics of series, shunt and compound motors.(9)
(ii) Explain the Ward Leonard method of speed control of dc shunt motor. (Marks 7)

12. (a) (i) Derive the emf equation of a transformer. (Marks 10)
(ii) A single phase transformer is rated at 240/120 V, 50 Hz, Find voltage and frequency of secondary at no-load (1) if primary voltage is 120 V, 25 Hz and (2) if primary voltage is 240 V dc. (Marks 6)
Or
(b) (i) Deduce the equivalent circuit of 1-ph transformer. (Marks 6)
(ii) A 1-ph transformer is rated at 10 KVA, 50 Hz. The secondary rated voltage is 240 V and the turns ratio is 10. The resistance and leakage reactant as referred to primary are 8.4 and 13.7 respectively. Find voltage regulation at full-load and power factors of 0.8 lagging, 0.8 leading and unity. (Marks 10)

13. (a) (i) Explain the principle of operation of 3-ph induction motor and (Marks 5)
(ii) A 3-ph, 6 pole 50 Hz cage motor is running with a slip of 4%. Find speed of the rotating field relative to the stator winding, motor speed and frequency of emf induced in the rotor. (Marks 6)
(iii) Briefly explain the starting of squirrel cage motor using star-delta starter. (Marks 5)
Or
(b) Discuss the operation of following types of 1-ph induction motors with neat circuit diagrams and speed-torque characteristics.
(i) Capacitor-start, capacitor-run motor (Marks 8)
(ii) Shaded pole motor. (Marks 8)

14. (a) Briefly discuss the construction of the following :
(i) Stator of synchronous machine (Marks 8)
(ii) Salient pole and cylindrical rotors. (Marks 8)
Or
(b) Explain the construction and operation of the following :
(i) Reluctance motor (Marks 8)
(ii) Hysteresis motor. (Marks 8)

15. (a) (i) Draw the one-line diagram of a typical power supply system. Mark all the components. (Marks 10)
(ii) What are the advantages of dc transmission systems over ac transmission systems? Explain. (Marks 6)
Or
(b) (i) What are the main components used in transmission and distribution systems? Write down the functions of each. (Marks 8)
(ii) Compare overhead lines and underground cable systems. (Marks 8)

PRINCIPLES OF COMMUNICATION IT2202 NOV/DEC 2010 ANNA UNIVERSITY QUESTION PAPER

B.E./B.Tech. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2010
Third Semester

Information Technology
IT 2202 — PRINCIPLES OF COMMUNICATION
(Regulation 2008)

Time : Three hours Maximum : 100 Marks
PART A — (10 × 2 = 20 Marks)

1. Why should the modulation index of AM be less than 1?
2. Draw FM and PM waveforms.
3. What is Shannon limit for information capacity?
4. Draw Costas loop circuit.
5. Define Companding.
6. Distinguish between DM and ADM.
7. What is the significance of PN sequence?
8. What are the types of FH spread spectrum technique?
9. What is a transponder?
10. Derive the velocity of a Geo Synchronous Satellite.

PART B — (5 × 16 = 80 Marks)

11. (a) (i) What is the principle of Amplitude modulation? Derive expression for the AM wave and draw its spectrum. (Marks 8)
(ii) Describe the frequency analysis of Angle modulated waves. Explain their Bandwidth requirements. (Marks 8)

Or
(b) (i) A modulating signal of 2 cos5000t is amplitude modulated over a carrier signal of 5cos20000t . Derive expressions for the modulation index, LSB and VSB frequencies, Bandwidth and the ratio of Side
Band Power in the Total Power of AM wave. (Marks 8)
(ii) Explain the principle of Angle Modulation. Derive and explain phase deviation, Modulation index, frequency deviation and percent modulation. (Marks 8)

12. (a) (i) Draw FSK Transmitter and explain. Describe its Bandwidth Considerations. (Marks 8)
(ii) For a BPSK modulator with a Carrier frequency of 70 MHz and an input bit rate of 10 Mbps, determine the maximum and minimum upper and lower side frequencies, draw the output spectrum, determine the minimum Nyquist bandwidth, and calculate the baud (Assume fa = 5 MHz). (Marks 8)

Or
(b) (i) Draw and explain the operations of Non-coherent and coherent FSK modulators. (Marks 8)
(ii) Draw QPSK modulator and explain. Describe its Bandwidth considerations. (Marks 8)

13. (a) (i) Describe in detail the PCM technique with focus on its sampling rate, and signal to quantization Noise ratio. (Marks 8)
(ii) What is ISI? Explain the applications of eye pattern to detect ISI. (Marks 8)

Or

(b) (i) With a block diagram, explain the adaptive Delta Modulation technique. (Marks 8)
(ii) What is DPCM? Explain its principle with neat block diagram. (Marks 8)

14. (a) (i) Draw the circuit of a P-N sequence generator and explain. (Marks 8)

(ii) Describe the concept of FHSS in detail. (Marks 8)
Or
(b) (i) Explain the principle of DSSS with coherent binary PSK. (Marks 8)
(ii) Compare between the TDMA and CDMA wireless communication systems. (Marks 8)

15. (a) (i) List any four advantages and disadvantages of Geo Synchronous Satellites. (Marks 4)
(ii) Describe in detail the operation of Optical Sources. (Marks 12)

Or
(b) (i) State and describe Kepler's laws. (Marks 4)
(ii) Describe in detail the operations of various types of optical detectors. (Marks 12)