Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-005-007
Toute onde FM modulée par une tonalité unique a :
- Aune fréquence de bande latérale
- Bun nombre infini de fréquences de bande latérale
- Cdeux fréquences de bande latérale
- Dquatre fréquences de bande latérale
Correct answer: B — un nombre infini de fréquences de bande latérale. Question tirée de la banque officielle d'ISDE.
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 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