What does HUM modulation refer to?

HUM modulation refers specifically to the distortion of amplitude in a signal. This phenomenon often occurs in audio and other electronic systems where low-frequency noise can interfere with the desired signals. The "hum" typically refers to a specific frequency of interference (such as 60 Hz hum from electrical sources) that can affect the amplitude of the signal being transmitted, leading to distortion in the output.

In contrast, while enhancement of signal clarity relates to improving the fidelity of the transmitted information, it does not define HUM modulation. High-frequency sounds do not encapsulate the concept of HUM modulation, which is more about low-frequency noise affecting amplitude rather than the presence of sound itself. Although modulation with a different frequency could be a method of altering signals, it does not address the specific issue of distortion associated with HUM modulation. Thus, the primary recognition of HUM modulation is its direct connection to amplitude distortion in signals.