Define the term 'digital signal'.

A digital signal is defined as one that represents data as discrete values, which means it conveys information in distinct and separate units rather than as continuous waveforms. In a digital signal, information is typically represented in binary form (0s and 1s), allowing for precise and reliable transmission and processing of data. This characteristic makes digital signals robust against noise and interference, providing advantages in data integrity and efficiency in communication systems.

The other options do not accurately describe the nature of a digital signal. Continuous waveforms represent analog signals, which can vary smoothly over time. The reference to a signal having no specific format does not apply to digital signals, as they are defined by strict standards and protocols. Finally, the idea that a signal can only transmit audio data is misleading, as digital signals are used in a wide range of applications beyond audio, including video, data processing, and telecommunications.