PHYSICAL LAYER AND TRANSMISSION MEDIA
BANDWIDTH UTILIZATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Large transmission bandwidth
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Small transmission bandwidth
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Fixed transmission bandwidth
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Fixed null bandwidth
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Detailed explanation-1: -Why spread spectrum technique is inefficient for a single user? Explanation: Spread spectrum systems are bandwidth inefficient for single users. But in spread spectrum systems, many users can simultaneously use the same bandwidth without significantly interfering with one another.
Detailed explanation-2: -Disadvantages of Direct Sequence Spread Spectrum (DSSS) The Direct Sequence Spread Spectrum or DSSS system takes large acquisition time; that’s why its performance is slow. It requires wide-band channels with small phase distortion. In DSSS, the pseudo-noise generator generates a sequence at high rates.
Detailed explanation-3: -There are two predominant techniques to spread the spectrum: 1) Frequency hoping (FH), which makes the narrow band signal jump in random narrow bands within a larger bandwidth. 2) Direct sequence (DS) which introduces rapid phase transition to the data to make it larger in bandwidth.