communication-systems Question 23
Question: Q. 1. (i) Which mode of wave propagation is suitable for television broadcast and satellite communication, and why ? Draw a suitable diagram depicting this mode of propagation of wave.
U] [O.D. Comptt. I, II, III 2012]
(ii) Block diagram of a receiver is shown in the figure.
(a) Identify ’ $X$ ’ and ’ $Y$ ‘.
(b) Write their functions.
[Delhi I, II, III 2013]
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Solution:
Ans. (i) The skywave propagation is suitable for television broadcast and satellite communication.
$1 / 2$
The radio waves from the transmitting antenna can reach the receiving antenna $R$ from the different layers of ionospheres as shown in figure. $1 / 2$
(Say F-layer)
(ii) (a) $X$ : IF stage
$Y$ : Amplifier
(b) The carrier frequency is changed to a lower frequency by intermediate frequency (IF) stage preceding the detection.
An amplifier increases the strength of the detected signal.
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