Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-008-005
What type of error control system is used in AMTOR ARQ (Mode A)?
- A Each character is sent twice
- B Mode A AMTOR does not include an error control system
- C The receiving station automatically requests repeats when needed
- D The receiving station checks the frame check sequence (FCS) against the transmitted FCS
Correct answer: C — The receiving station automatically requests repeats when needed. From the official ISED question bank, verified word for word.
Why
In AMTOR ARQ, the receiving station listens carefully and automatically asks the sender to repeat any part of the message that arrives with errors, ensuring the text is copied correctly before moving on. 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.