Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-009-003
What term is used to describe a spread spectrum communications system in which a very fast binary bit stream is used to shift the phase of an RF carrier?
- A Direct sequence
- B Frequency hopping
- C Phase companded spread spectrum
- D Binary phase-shift keying
Correct answer: A — Direct sequence. From the official ISED question bank, verified word for word.
Why
Direct sequence is the right term because it describes a system where a fast stream of binary bits directly shifts the phase of the radio carrier to spread the signal across a wider frequency band. The full explanation — and one for every question — is in Pro.
Practise this section
Transmitters, modulation and processing: AM, FM, SSB, keying, speech processing, and the numbers behind occupied bandwidth.