What does the term "noise figure" measure in a receiver?

The term "noise figure" measures the performance degradation of the signal-to-noise ratio as a signal passes through a receiver. It quantifies how much noise is added by the receiver itself compared to the thermal noise inherent to the input signal. Essentially, it indicates how effectively a receiver can amplify a weak signal amidst background noise.

A lower noise figure indicates better performance, meaning the receiver has less impact on the overall signal quality. When designing communication systems, minimizing the noise figure is crucial for achieving optimal signal clarity and integrity, which is especially important in scenarios where the received signal is weak.

Understanding noise figure is essential in radio frequency (RF) engineering and communications, as it directly affects the sensitivity and performance of receivers. Options that focus on frequency response, component quality, or power efficiency do not capture this fundamental aspect of how noise impacts signal quality in receivers.