Basic Qualification · B-008 Interference and suppression · B-008-005-007
A strong interfering signal is very close to your receive frequency. Which type of filter can effectively suppress it?
- A Low-pass
- B Band-reject
- C Notch
- D High-pass
Correct answer: C — Notch. From the official ISED question bank, verified word for word.
Why
A Notch filter is the right choice because it acts like a very narrow trap, removing just one specific frequency while letting everything else pass. 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.