ARRL Technician Practice Exam

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

1. Sensitivity

2. Impedance

3. Gain

4. Bandwidth

The correct answer is: Sensitivity

Sensitivity refers to a receiver's ability to detect weak signals. It is a critical characteristic because it dictates how faint a signal can be for the receiver to still accurately interpret it. A receiver with high sensitivity can pick up lower power signals, making it more effective in environments where the signal strength may be minimal due to distance, interference, or other factors. Impedance pertains to how much resistance a circuit presents to alternating current, which is not directly related to signal detection capabilities. Gain measures the increase in power or amplitude of a signal during processing, and while it can enhance the strength of a detected signal, it does not contribute to the ability to initially sense or detect that signal. Bandwidth refers to the range of frequencies that a receiver can process, impacting the types of signals it can access; however, it does not define the receiver's sensitivity to those signals. Thus, sensitivity is the term that specifically addresses the receiver's capability to detect the presence of a signal.