Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-005-011
What is the frequency deviation for a 12.21- MHz reactance-modulated oscillator in a +/- 5-kHz deviation, 146.52-MHz FM-phone transmitter?
- A+/- 12 kHz
- B+/- 5 kHz
- C+/- 41.67 Hz
- D+/- 416.7 Hz
Correct answer: D — +/- 416.7 Hz. From the official ISED question bank, verified word for word.
Why
The oscillator runs at 12.21 MHz while the final transmitter operates at 146.52 MHz, meaning the signal is multiplied by a factor of twelve to reach the target 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