Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-001-009
Un circuit dont le fonctionnement dépend d'une rétroaction positive pourrait être :
- Aun mélangeur
- Bun détecteur
- Cun amplificateur audiofréquence
- Dun oscillateur à fréquence variable
Correct answer: D — un oscillateur à fréquence variable. Question tirée de la banque officielle d'ISDE.
Why
A variable-frequency oscillator needs positive feedback to keep generating a steady signal at a specific pitch, which can be adjusted to change that frequency. 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