Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-005-005
When the transmitter is not modulated, or the amplitude of the modulating signal is zero, the frequency of the carrier is called its:
- A frequency deviation
- B frequency shift
- C modulating frequency
- D centre frequency
Correct answer: D — centre frequency. From the official ISED question bank, verified word for word.
Why
When a transmitter sends a signal without any voice or data changing it, the radio wave sits at a steady pitch. 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.