Extra exam question E8B06
Subelement E8, SIGNALS AND EMISSIONS· Group E8B
What is the deviation ratio of an FM phone signal having a maximum frequency swing of plus or minus 7.5 kHz if the highest modulation frequency is 3.5 kHz?
- A.2.14 (correct answer)
- B.0.214
- C.0.47
- D.47
WhyAn FM phone signal with a maximum frequency swing of plus or minus 7.5 kHz and a highest modulation frequency of 3.5 kHz has a deviation ratio of about 2.14. Deviation ratio equals the maximum frequency deviation divided by the highest modulating frequency: 7.5 kHz divided by 3.5 kHz works out to approximately 2.14, answer A. The other figures come from inverting that ratio, applying an unrelated scale factor, or misplacing a decimal point.
Published 2026-08-28 · Last updated 2026-08-28 · Question text is verbatim from the 2024-2028 NCVEC Element 4 pool (public domain); the explanation above is original writing, see our methodology.
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