Why is a diplex filter used at each downstream output port in a distribution amplifier?

A diplex filter is employed at each downstream output port in a distribution amplifier primarily to separate upstream and downstream RF signals. This separation is crucial in communication systems, particularly in those that operate in bi-directional modes, allowing both upstream (signals from the subscriber back to the headend) and downstream (signals from the headend to the subscriber) traffic to coexist without interference.

By effectively differentiating between the frequencies designated for upstream and downstream signals, the diplex filter ensures that the desired signals can pass through to their respective paths without attenuation or distortion. This function is essential for maintaining the integrity of the signals in both directions, facilitating efficient communication and preventing cross-talk between the two channels.

The other options relate to different aspects of signal management, but their objectives do not align with the primary function of diplex filters in this context. For instance, while improving overall signal clarity and bandwidth could be related to filter design and deployment, the specific role of a diplex filter focuses on the separation of signal paths rather than enhancement of power savings or bandwidth. Thus, the most accurate rationale for employing diplex filters in distribution amplifiers is their ability to effectively separate upstream and downstream signals.