What device processes modulated signals and has four basic functions: reception, detection, selection, and sensitivity?

The device that processes modulated signals and performs the four essential functions of reception, detection, selection, and sensitivity is indeed a receiver.

Receivers are critical components in communication systems as they are designed to capture and decode signals transmitted over various mediums. The reception function allows the receiver to pick up signals from the air or other transmission mediums, while detection refers to the ability of the receiver to convert these signals into a usable form, often transforming them back into audio or data.

Selection involves filtering the received signals to isolate the desired signal from unwanted noise or other signals by tuning into a specific frequency. Sensitivity is a measure of how well the receiver can detect weaker signals amidst interference. This combination of functions enables receivers to effectively retrieve and process modulated signals, making them essential for communication tasks in various applications.