What is a characteristic of a digital signal?

A digital signal is characterized mainly by its representation of information through discrete values, which allows it to convey data in a clear and distinct manner. The reason that sending information as pulses of uniform amplitude is a characteristic of digital signals is that digital communication relies on binary states (typically represented as 0s and 1s). Each pulse corresponds to a specific state, resulting in a consistent and stable signal that is less affected by variations in amplitude compared to analog signals.

In contrast to this, the other options present different features that do not describe digital signals. For instance, having infinite states is a characteristic of analog signals, which can continuously vary over a range without discrete levels. Similarly, carrying information continuously implies a smooth, uninterrupted transmission, aligning more with analog signals. Lastly, while noise can impact any signal type, it is particularly problematic for analog signals due to their continuous nature. Digital signals, on the other hand, are generally more robust against noise, due to their defined states which can be easily distinguished even amid some level of interference.