Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-005-004
What is the deviation ratio of an FM phone transmitter having a maximum frequency swing of plus or minus 7.5 kHz and accepting a maximum modulation rate of 3.5 kHz?
- A 0.214
- B 2.14
- C 0.47
- D 47
Correct answer: B — 2.14. From the official ISED question bank, verified word for word.
Why
The deviation ratio is found by dividing the maximum frequency swing of 7.5 kHz by the highest modulation rate of 3.5 kHz, which equals roughly 2.14. The full explanation — and one for every question — is in Pro.
Practise this section
Transmitters, modulation and processing: AM, FM, SSB, keying, speech processing, and the numbers behind occupied bandwidth.