Extra exam question E8D02

WhyDirect sequence is the spread spectrum technique that uses a high-speed binary bit stream to shift the phase of an RF carrier. Direct sequence is the spread spectrum technique that uses a high-speed binary bit stream (a pseudorandom spreading code) to rapidly shift the phase of an RF carrier, spreading the transmitted signal's energy across a much wider bandwidth than the original data alone would need, answer B. Frequency hopping instead rapidly changes the carrier's frequency rather than its phase, and "binary phase-shift keying" alone and "phase compandored spread spectrum" don't describe this specific direct-sequence spreading technique.