What is an advantage of a constant-k filter?

A constant-k filter is designed to have a consistent response characteristic in terms of its bandwidth and its attenuation outside the pass band. One of the major advantages of this type of filter is that it exhibits high attenuation for signals that are at frequencies significantly removed from the pass band. This means that it effectively suppresses unwanted signals and noise outside of the desired frequency range, ensuring that the desired signals are maximized and interference is minimized.

This high attenuation characteristic facilitates clear signal transmission, especially in communications where it is crucial to reduce noise and improve the clarity of the transmitted signal.

The other options, while they touch on different characteristics of filters, do not accurately describe the primary advantage of a constant-k filter. High selectivity pertains more to how precisely a filter can isolate distinct frequency components, while equal gain across all frequencies is a characteristic of a different type of filter configuration. Moreover, requiring complex circuitry is not an advantage; in fact, constant-k filters can often be simpler to implement than counterparts that offer different filtering characteristics.