Which of the following describes the primary function of a receiver in a radar system?

The primary function of a receiver in a radar system is to collect and amplify weak echoes. In radar technology, when a radar signal is transmitted, it travels through the atmosphere and reflects off objects in its path, such as aircraft or terrain. These reflections, known as echoes, are often very weak due to the distance they travel and the scattering effect on the radar waves.

The receiver is designed specifically to detect these faint echoes and convert them into a usable signal. It amplifies these weak signals so that they can be properly processed for further analysis, such as determining the range, speed, and direction of the detected objects. By enhancing these echoes, the receiver plays a crucial role in ensuring the radar system can effectively identify and track objects, which is essential for operations like air traffic control and surveillance.

The other options describe functions that are not primarily associated with the receiver's role. Transmitting signals pertains to the transmitter, generating output signals may involve processing units, and filtering frequencies is a specific part of signal processing but does not capture the receiver's main purpose of detecting and amplifying echoes.