Basic Qualification · B-008 Interference and suppression · B-008-005-011
A filter attenuates frequencies above its cut-off frequency of 40 MHz. What type of filter is it?
- A Notch
- B Low-pass
- C Band-pass
- D High-pass
Correct answer: B — Low-pass. From the official ISED question bank, verified word for word.
Why
A low-pass filter lets signals below a set limit pass through while blocking those above it. 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.