Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-005-002
Quel est l'indice de modulation d'un émetteur FM produisant une excursion instantanée de 6 kHz lorsque la fréquence modulante est de 2 kHz?
- A3
- B0,333
- C2 000
- D6 000
Correct answer: A — 3. Question tirée de la banque officielle d'ISDE.
Why
The modulation index equals the frequency deviation divided by the modulating frequency, so dividing the 6 kHz deviation by the 2 kHz tone gives exactly 3. 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