Extra exam question E4C04
Subelement E4, AMATEUR PRACTICES· Group E4C
What is the noise figure of a receiver?
- A.The ratio of atmospheric noise to phase noise
- B.The ratio of the noise bandwidth in hertz to the theoretical bandwidth of a resistive network
- C.The ratio in dB of the noise generated in the receiver to atmospheric noise
- D.The ratio in dB of the noise generated by the receiver to the theoretical minimum noise (correct answer)
WhyA receiver's noise figure is the ratio in dB of the noise the receiver generates to the theoretical minimum noise. A receiver's noise figure is expressed in dB as the ratio of the actual noise the receiver generates to the theoretical minimum noise a perfect, noiseless receiver would still have due to fundamental thermal noise limits, answer D. It's not a ratio involving atmospheric noise, and it isn't a bandwidth ratio, those describe different concepts from what noise figure actually measures.
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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