Basic Qualification · B-008 Interference and suppression · B-008-004-011
Harmonics may be produced in the RF power amplifier of a transmitter if:
- A modulation is applied to a high-level stage
- B excessive drive signal is applied to it
- C the output tank circuit is tuned to the fundamental frequency
- D the oscillator frequency is unstable
Correct answer: B — excessive drive signal is applied to it. From the official ISED question bank, verified word for word.
Why
When you push too much signal into the RF power amplifier, the tube or transistor gets overwhelmed and cannot copy the input wave cleanly. The full explanation — and one for every question — is in Pro.
Practise this section
When things interfere: harmonics, overload, RFI to and from your station, filters, ferrites and how to fix the neighbour's TV.