Janardan Rai Nagar Rajasthan Vidyapeeth 2007 B.Tech Aeronautical Engineering AVIONICS – I - Question Paper

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BACHELOR IN TECHNOLOGY
(SEMESTER - V) (AERONAUTICAL)
BTAE2 - AVIONICS – I
TIME: 03 HOURS MAX. MARKS: 75

GENERAL INSTRUCTIONS:
1. Question paper is divided into 3 groups
2. Each group is of 25 marks every
3. Figure to the right in bracket shows mark
4. Assume suitable data if necessary
GROUP A: ans any 3 ques.. ques. No. one is compulsory.
Q.1. What are the disadvantages of J3E with respect to A3E? (5)
Q.2. Prove, with a diagram, that electromagnetic waves passing from a denser to a rarer medium are bent away from the normal . ? (10)
Q.3. Discuss the reflection mechanism whereby electromagnetic waves are bent back by a layer of the ionosphere. Include in your discussion a description of the virtual height of a layer. The fact that the virtual height is greater than the true height proves something about the reflection mechanism. What is this ? (10)
Q.4. Derive the Hartley legal regulations (verbally ) for binary code, using the CCITT-2 code to prove the relation ? (10)
Q.5. In what way is pulse-code modulation various from other modulation systems, pulse or otherwise, previously studied? What makes it a digital system ? (10)
GROUP B: ans any 3 ques.. ques. No. six is compulsory.
Q.6. The tuned circuit of the oscillator in a sample AM transmitter employs a 50 microhenry (50- coil and a 1-nanofarad (1-nF) capacitor. If the oscillator output is modulated by audio frequencies up to 10 kHz. What is the frequency range occupied by the sidebands? (5)
Q.7. 3-kW source. Both are presumed to be omnidirectional point soruces. The 2nd value is incidentally, the equivalent power density on the ground from a communications satellite in orbit. (10)
Q.8. A deep-space high-gain antenna and receiver system have a noise figure such that a minimum received power of 3.7 x 10-18 is needed for satisfactory communication. What must be the transmitting power from a Jupiter probe, situated 800 million km from the earth ? presume that the transmitting antenna is isotropic, and the equivalent area of the receiving antenna has an Area of 8400 m2 (10)
Q.9. An HF radio system is used to transmit info by means of a binary code. The transmitting power is 50 W, and the noise level at the receiver input is such that the consequent fault rate is just acceptable. The operator now decides to double the info flow rate by using a 4 – level code instead of the binary code. To what level must the transmitting power be raised to retain the identical fault rate ? (10)
Q.10. At the input to the receiver of a standard telephone channel, the noise power is 50 W and the signal to power is 20 mW. compute the Shannon limit for the capacity of the above channel under these conditions., and then when the signal power is halved. ? (10)

GROUP C: All ques. are Compulsory.
Q.11 Fill in the blanks (each ques. carries two marks)
(i) The behaviour of waves in circular waveguide is the identical as in __________ .
(ii) The physical length of the antenna must equal __________ of the transmitte signal.
(iii) The antenna must have the ability to match the __________.
(iv) The phenomenon of known as __________.
(v) __________ is describe as the option of finite set of message.

Q.12 Multiple option ques.. (Each ques. carries two marks)
(i) Indicate which of the subsequent is not a binary code
(a) morse (b) baudot (c) ccitt – 2. (d) arq.
(ii) __________ is a low power efficiency micro wave oscillator
(a) cfa (b)coaxialmagnetron (c)reflex (d)traveling wave magnetron
(iii) __________ can evan measure the direction of the target, in addition to its speed.
(a) the mti system (b) moving target plotting on the ppi (c) fm radar(d) cw radar
(iv) Indicate the antenna that is not wide band.
(a) discone (b) folded dipole (c) helical (d) marconi
(v) The basic supergroup is formed in
(a) gte (b) cte (c) fdm (d) tdmQ.13

actual or false (each ques. carries one mark).
(i) Modulation is used to decrease the bandwidth .
(ii) In an SSB transmitter, 1 is most likely to obtain a tuned modulator .
(iii) The absorption of radio waves by the atmosphere depends on their frequency .
(iv) The most common modulation system used for telegraphy is pulse code modulation .
(v) The SWR on transmission line is infinity , if line is terminated in a complex impedance.


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Earning:   Approval pending.