Question
Which of the following noise figure values is typical of a low-noise UHF preamplifier?
Answer Options
- A) 0.5 dB
- B) -10 dB
- C) 44 dBm
- D) -20 dBm
Correct Answer: A
Explanation
The noise figure (NF) quantifies how much a device degrades the signal-to-noise ratio (SNR) as the signal passes through it. In low-noise preamplifiers (LNAs) used for weak-signal reception at UHF and microwave frequencies (such as EME or satellite work), the goal is to have an NF as close to 0 \text{ dB} (the theoretical minimum) as possible.
Achieving an NF below 1 \text{ dB} requires careful design, component selection (like GaAs or GaN FETs), and minimization of losses. A noise figure value of 0.5 \text{ dB} is typical and desirable for a high-quality, modern low-noise UHF preamplifier. The other options are incorrect units or represent very poor performance (high noise figure).
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