What unit's primary function is to accept the output of the receiver/exciter (REX), and decide, for every range and azimuth cell in the radar coverage area, whether a moving target is present or not?

The target processor is essential in radar systems as it takes the output from the receiver/exciter (REX) and analyzes it to discern whether a moving target is detected in each specified range and azimuth cell. This function is critical for effective radar operation, as it involves processing the data collected by the radar to identify targets based on factors such as speed and movement patterns, thereby distinguishing them from background noise and clutter.

The target processor employs various algorithms and techniques to evaluate the received signals, filtering irrelevant information and focusing on the characteristics indicative of moving objects. This decision-making process is pivotal in applications such as air traffic control and military radar systems, where accurate target identification is crucial for safety and operational effectiveness.

The other options serve different functions within the radar system. For example, the radar interface suppressor primarily manages signal interference, while the binary integrator processes digital signals to improve signal-to-noise ratio. The video amplifier, on the other hand, amplifies video signals for better display but does not perform target detection. Thus, the target processor uniquely fulfills the role of determining the presence of moving targets, making it the correct choice.