What term describes the ability of a receiver to detect the presence of a signal?

The term that describes the ability of a receiver to detect the presence of a signal is sensitivity. Sensitivity refers to the minimum amount of input signal power that a receiver can detect and process effectively. In practical terms, a sensitive receiver can pick up weaker signals, making it crucial for effective communication, especially in situations where signals may be weak or subject to attenuation.

For example, in amateur radio, having a receiver with high sensitivity allows the operator to hear distant stations and improve overall communication quality. Sensitivity is an important specification when evaluating receivers because it impacts how well the device can operate under various conditions, including noise and interference.

In contrast, linearity relates to how well a system can amplify signals without distortion. Selectivity describes the receiver's ability to differentiate between closely spaced frequencies or channels. Total harmonic distortion pertains to the linearity and quality of amplification, specifically how much distortion is introduced in the output signal compared to the original input. Understanding these terms helps in selecting the right equipment for effective communication in amateur radio.