COMPUTER NETWORKS AND COMMUNICATIONS
WIRELESS COMMUNICATION TECHNOLOGIES
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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true
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false
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Either A or B
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None of the above
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Detailed explanation-1: -The three most important effects are: Rapid changes in signal strength over a small travel distance or time interval. Random frequency modulation due to varying Doppler shifts on different multipath signals. Time dispersion (echoes) caused by multipath propagation delays.
Detailed explanation-2: -Explanation: Rapid changes in signal strength over a small travel distance are caused due to multipath. It causes random frequency modulation due to varying Doppler shifts on different multipath signals. Time dispersion is also caused by multipath propagation delays.
Detailed explanation-3: -Multipath propagation, an inherent feature of a mobile communications channel, results in a received signal that is dispersed in time. Each path has its own delay and the time dispersion leads to a form of intersymbol interference. Delay spread is a measure of the multipath profile of a mobile communications channel.
Detailed explanation-4: -The effect is to induce a slope in the system frequency response, or even to create multiple peaks or notches in the received signal spectrum. This is known as frequency selective fading. The path length difference at which frequency selective fading starts to become significant depends on the signal bandwidth.