Digital representation makes use of physically arbitrary symbols.
That is, the physical structure of the symbol is chosen by social convention. The physical structure IS the information that is, an analog signal changes in proportion to the information it represents. The gas gauge on my car, the loudness of my voice, the mercury in a thermometer. The cybernetic definition implies that all 6 sensory modalities are capable of both analog and digital representations. It is dynamic a picture can become an icon over time, and an icon can become an arbitrary symbol.