Which term describes the signal-to-noise ratio?

• A. A ratio used to determine engine fuel efficiency.
• B. An indication of signal strength received compared to background noise, which is a measure of the adequacy of the received signal.
• C. A calculation for determining cruise altitude.
• D. A method for calibrating altimeters.

Answer: (B)

The signal-to-noise ratio measures how strong the received signal is relative to background noise. It tells you how adequate the received signal is for reliable interpretation: a higher ratio means the signal stands out clearly from the noise, while a lower ratio means the noise can obscure the signal. In aviation communications and radar, this ratio directly affects readability and detectability. The other options describe engine efficiency, cruise altitude calculations, or altimeter calibration, which are not related to how clearly a signal is received. So the best description is the comparison of the signal strength to the surrounding noise, indicating the adequacy of the received signal.