22334 2022 Summer Question Paper PDF

21222 22334 3 Hours / 70 Marks Seat No. 15 minutes extra for each hour Instructions : (1) All Questions are compulsory. (2) Answer...

21222 22334 3 Hours / 70 Marks Seat No. 15 minutes extra for each hour Instructions : (1) All Questions are compulsory. (2) Answer each next main Question on a new page. (3) Illustrate your answers with neat sketches wherever necessary. (4) Figures to the right indicate full marks. (5) Assume suitable data, if necessary. (6) Use of Non-programmable Electronic Pocket Calculator is permissible. (7) Mobile Phone, Pager and any other Electronic Communication devices are not permissible in Examination Hall. Marks 1. Attempt any FIVE : 10 (a) Classify types of Noise. (b) In AM, modulating frequency is 10 kHz and carrier frequency is 1 MHz. Determine the resultant frequency components. (c) Write mathematical expression representing FM wave. (d) Draw block diagram of High level AM transmitter. (e) Draw FM wave for modulating signal of 100 Hz 1 Vp – p. (f) Define electromagnetic polarization and list its types. (g) Illustrate concept of virtual height with neat labelled diagram with respect to wave propogation. [1 of 4] P.T.O. 22334 [2 of 4] 2. Attempt any THREE : 12 (a) State frequency range of the following : (i) Audio frequency (ii) IR frequency (iii) Voice frequency (iv) High frequency (b) Show that AM wave consists of two side bands and a carrier. Prove that bandwidth of AM is double of modulating frequency. (c) A superheterodyne radio receiver with an intermediate frequency of 455 kHz is turned to a station operating at 1200 kHz. Find associated image frequency and local oscillator frequency. (d) Compare sky wave propogation and space wave propogation (Any four points). 3. Attempt any THREE : 12 (a) State and explain the concept of Transmission bandwidth. (b) Calculate the percentage power saving of an SSB signal if the AM wave is modulated to a depth of (i) 100% (ii) 50%. (c) Draw block diagram of superheterodyne AM receiver and explain working of each block. (d) Draw a neat sketch of Duct propogation and explain its basic principle. 4. Attempt any THREE : 12 (a) Distinguish between Half duplex and Full duplex communication (Any four points). (b) Explain effect of modulation index on AM wave with waveforms. 22334 [3 of 4] (c) Explain the terms selectivity and sensitivity with respect to radio receiver. Illustrate with respective curves. (d) Describe Troposphere scatter propogation along with sketch. (e) Draw radiation pattern of given antennas : (i) Yagi-Uda antenna (ii) Loop antenna (iii) Dish antenna (iv) Horn antenna 5. Attempt any TWO : 12 (a) (i) Define modulation index of FM wave. (ii) The equation of FM wave is eFM = 20 sin (108t + 4 sin103 t). Calculate (1) Carrier frequency (2) Modulating frequency (3) Modulation Index (4) Power dissipated in 10  resistor (b) State need of AGC. List types of AGC. Draw and explain AGC characteristics for delayed, ideal and simple AGC. (c) Define radiation pattern of an antenna. Draw radiation pattern for resonant dipole (i) l = 2 (ii) l= (iii) l = 3/2 (iv) l = 3 P.T.O. 22334 [4 of 4] 6. Attempt any TWO : 12 (a) State relation between the transmitted power and carrier power in AM. Show effect of modulation index on total transmitted power. (b) Define fading. List major causes of fading and explain them. (c) Describe Yagi-Uda antenna with a neat sketch. State any two advantages of Yagi-Uda antenna. _______________