Theoretically, analog systems are superior to digital systems  A signal in a pure analog system can be infinitely detailed, while digital systems cannot produce signals that are more precise than their digital units  With this theoretical advantage there is a practical disadvantage, however  Since there is no limit on the potential detail of the signal, the duplication of an analog representation allows tiny variations from the original, which are errors
These errors tend to accumulate as signals are duplicated, until this noise obliterates the information embodied in the original signal
Digital systems are preferable to analog systems when the signal must be reproduced many times.