Virtual Labs

Frequency Selective Fading

1. What is the key characteristic of 'frequency selective fading'?

a: All frequency components of the signal fade in the exact same way. Explanation

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b: Different frequency components of the signal experience different amounts of fading. Explanation

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c: The signal's amplitude increases uniformly across all frequencies. Explanation

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d: The fading only affects the phase, not the amplitude, of the signal. Explanation

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2. What does 'delay spread' measure in a wireless channel?

a: The time it takes for a signal to leave the transmitter. Explanation

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b: The difference in arrival time between the first and last multipath components. Explanation

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c: The speed at which the receiver is moving. Explanation

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d: The total time duration of a single data bit. Explanation

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3. Frequency selective fading occurs when the signal's bandwidth is...

a: smaller than the channel's coherence bandwidth. Explanation

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b: larger than the channel's coherence bandwidth. Explanation

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c: exactly equal to the channel's coherence bandwidth. Explanation

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d: not related to the channel's coherence bandwidth. Explanation

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4. What is the 'coherence bandwidth' of a channel?

a: The total bandwidth allocated to the service provider. Explanation

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b: The range of frequencies that experience similar or correlated fading. Explanation

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c: The speed at which the signal frequencies change. Explanation

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d: The bandwidth that is completely free of any interference. Explanation

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5. A large delay spread in a channel will result in...

a: a very large coherence bandwidth. Explanation

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b: a very small coherence bandwidth. Explanation

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c: no coherence bandwidth. Explanation

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d: no fading. Explanation

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6. What is the primary negative consequence of frequency selective fading?

a: The signal's power becomes too high for the receiver. Explanation

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b: The signal arrives at the receiver too quickly. Explanation

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c: It causes intersymbol interference (ISI), where symbols overlap. Explanation

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d: It causes all frequencies to be lost permanently. Explanation

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7. If a channel has a very small delay spread (much smaller than the symbol period), what type of fading will the signal likely experience?

a: Frequency selective fading Explanation

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b: Flat fading Explanation

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c: Fast fading Explanation

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d: Doppler fading Explanation

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8. Intersymbol interference (ISI) is a major problem when...

a: the delay spread is very small compared to the symbol period. Explanation

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b: the delay spread is large and comparable to or greater than the symbol period. Explanation

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c: the signal bandwidth is very narrow. Explanation

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d: the channel experiences flat fading. Explanation

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9. How is the coherence bandwidth of a channel related to the delay spread?

a: They are directly proportional. Explanation

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b: They are inversely proportional. Explanation

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c: They are not related in any way. Explanation

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d: They are equal to each other. Explanation

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10. A signal is considered to experience flat fading if its bandwidth is...

a: much larger than the coherence bandwidth. Explanation

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b: much smaller than the coherence bandwidth. Explanation

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c: equal to the delay spread. Explanation

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d: larger than the symbol period. Explanation

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