Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-009-009
What is direct-sequence spread spectrum?
- AThe carrier is amplitude modulated over range called the spread
- BThe carrier is frequency-companded
- CThe carrier is altered in accordance with a pseudo-random list of channels
- DThe carrier is phase-shifted by a fast binary bit stream
Correct answer: D — The carrier is phase-shifted by a fast binary bit stream. From the official ISED question bank, verified word for word.
Why
Direct-sequence spread spectrum works by rapidly changing the phase of the radio wave based on a fast stream of binary data, effectively spreading the signal across a wider bandwidth to resist interference. The full explanation — and one for every question — is in Pro.
Practise this section
Transmitters, modulation and processing is section A-005 of the Advanced exam: Transmitters, modulation and processing: AM, FM, SSB, keying, speech processing, and the numbers behind occupied bandwidth.
Drill A-005 — free, no account