Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-003-004
An advantage of keying the buffer stage in a transmitter is that:
- Akey clicks are eliminated
- Bthe radiated bandwidth is restricted
- Chigh RF voltages are not present
- Dchanges in oscillator frequency are less likely
Correct answer: D — changes in oscillator frequency are less likely. From the official ISED question bank, verified word for word.
Why
Keying the buffer stage means switching the signal on and off after the oscillator has already stabilized, so the oscillator itself never sees the sudden load changes that cause its frequency to drift. 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