Simplify the following text for a Grade 9 native English-speaking person.
Original: An analog or analog signal is any continuous signal for which the time varying feature ( variable ) of the signal is a representation of some other time varying quantity , i.e. , analogous to another time varying signal . It differs from a digital signal in terms of small fluctuations in the signal which are meaningful .
Simplified: An analog or analog signal is any continuous signal .