Question
Which describes spread spectrum frequency hopping?
Answer Options
- A) If interference is detected by the receiver, it will signal the transmitter to change frequencies
- B) RF signals are clipped to generate a wide band of harmonics which provides redundancy to correct errors
- C) A binary bit stream is used to shift the phase of an RF carrier very rapidly in a pseudorandom sequence
- D) Rapidly varying the frequency of a transmitted signal according to a pseudorandom sequence
Correct Answer: D
Explanation
Spread spectrum frequency hopping (\text{FHSS}) is a technique that uses a rapid, pseudo-random change in operating frequency to spread the signal’s energy over a wide range of spectrum. Unlike direct sequence, the signal is only at one frequency at a time, but it moves quickly and unpredictably across the band.
\text{FHSS} is accurately described as rapidly varying the frequency of a transmitted signal according to a pseudorandom sequence. The sequence of frequencies (the ‘hop set’) is known only to the transmitter and receiver. This makes the signal very difficult to track and jam, and it is highly robust against narrow-band interference, as the signal only dwells on any given interfering frequency for a short fraction of a second.
This topic was automatically created to facilitate community discussion about this exam question. Feel free to share study tips, memory tricks, or additional explanations!