Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-005-007
Any FM wave with single-tone modulation has:
- A four sideband frequencies
- B one sideband frequency
- C an infinite number of sideband frequencies
- D two sideband frequencies
Correct answer: C — an infinite number of sideband frequencies. From the official ISED question bank, verified word for word.
Why
When a carrier wave is frequency modulated by a single tone, the math of the signal creates a main carrier plus pairs of sidebands that stretch out forever, though they get weaker the further they go from the center. 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.