Extra exam question E4C05
Subelement E4, AMATEUR PRACTICES· Group E4C
What does a receiver noise floor of -174 dBm represent?
- A.The receiver noise is 6 dB above the theoretical minimum
- B.The theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature (correct answer)
- C.The noise figure of a 1 Hz bandwidth receiver
- D.The receiver noise is 3 dB above theoretical minimum
WhyA receiver noise floor of -174 dBm represents the theoretical noise in a 1 Hz bandwidth at the input of a perfect receiver at room temperature. A receiver noise floor of -174 dBm represents the theoretical thermal noise present in a 1 Hz bandwidth at the input of a perfect receiver operating at room temperature, the fundamental noise limit set by physics rather than by any real receiver's imperfections, answer B. It isn't a statement that a particular receiver is 6 dB or 3 dB above minimum, that's a separate noise figure specification, and it isn't itself a noise figure value.
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.
Related questions
- E4C01What is an effect of excessive phase noise in an SDR receiver’s master clock oscillator?
- E4C02Which of the following receiver circuits can be effective in eliminating interference from strong out-of- band signals?
- E4C03What is the term for the suppression in an FM receiver of one signal by another stronger signal on the same frequency?
- E4C04What is the noise figure of a receiver?
- E4C06How much does increasing a receiver’s bandwidth from 50 Hz to 1,000 Hz increase the receiver’s noise floor?