22334 Question Paper Summer 2023 PDF

22232 22334 3 Hours / 70 Marks Seat No. Instructions : (1) All Questions are compulsory. (2) Answer each next main Question on a new page. (3) Illu...

22232 22334 3 Hours / 70 Marks Seat No. 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 of the following : 2  5 = 10 (a) Define analog and digital signal with neat sketch. (b) Write down frequency range for the following in electromagnetic spectrum. (i) Voice frequencies (ii) Low frequencies (iii) High frequencies (iv) Extremely high frequencies (c) Write Carson’s rule to calculate Bandwidth of FM wave. (d) List any four advantages of modulation. [1 of 4] P.T.O. 22334 [2 of 4] (e) Write the IF value of (i) FM radio receiver (ii) MW band in AM (f) Sketch neat diagram of duct propagation. (g) Draw a sketch of half wave dipole antenna and it’s radiation pattern. 2. Attempt any THREE of the following : 3  4 = 12 (a) Compare synchronous and asynchronous transmission used in serial communication. (Any four points). (b) A superheterodyne radio receiver with an intermediate frequency of 455 KHz is tuned to a station operating at 1200 KHz Find the associated image frequency and local oscillator frequency. (c) Describe various layers of ionosphere with neat diagram. (d) Explain the structure of rectangular microstrip patch antenna with it’s radiation pattern. 3. Attempt any THREE of the following : 3  4 = 12 (a) Derive mathematical expression for AM wave. (b) Draw time domain and frequency domain representation for FM wave with proper labelling. (c) Draw the block diagram of AM Superheterodyne receiver and state function of each block. (d) Compare sky wave and space wave propagation (any four points). (e) Draw a neat sketch of Yagi-Uda antenna and it’s radiation pattern. State function of each element in antenna. 22334 [3 of 4] 4. Attempt any THREE of the following : 3  4 = 12 (a) Define simplex and half duplex modes of electronic communication using neat sketch. Also write applications for them. (b) Define modulation index for AM. State the effect of modulation index on AM wave with waveforms when m = 1, m < 1, m > 1. (c) Explain simple AGC and delayed AGC with neat sketches. (d) Define the following terms with neat sketches. (i) Virtual height (ii) Actual height (iii) Skip distance (iv) Maximum Usable frequency (e) Draw radiation pattern of the following resonant dipole antenna. (i) l = /2 (ii) l= (iii) l = 3/2 (iv) l = 3 where l is the length of dipole antenna. 5. Attempt any TWO of the following : 2  6 = 12 (a) Draw a block diagram of basic electronic communication system and explain function of each block. (b) Define sensitivity, selectivity and fidelity along with neat graphs and neat labelling. (c) Describe ground wave propagation with neat sketch. Write two advantages and disadvantages of it. P.T.O. 22334 [4 of 4] 6. Attempt any TWO of the following : 2  6 = 12 (a) A modulating signal 10 sin (2  102t) is used to modulate a carrier signal 14 sin (2  103t). Find modulation index, percentage modulation, frequencies of sidebands and their amplitude, Bandwidth of modulated signal. Also draw frequency spectrum of AM wave. (b) Explain the concept of pre-emphasis and de-emphasis with circuit diagram and characteristics used in FM system. (c) Draw constructional details of dish antenna. Describe it’s operating principle. Also draw it’s radiation pattern. _____________