<human>:  How does the author explain the difference between the noise in a system and the noise in a signal?
<bot>: The author explains the difference between the two in Chapter 2 of the book. In short, the author explains that noise is any unwanted disturbance that occurs in a system. A signal is a signal is a type of disturbance that is useful to the system. For example, a person talking is a signal that is useful to a person. Noise is not a signal, and noise is not useful to the system. The author also explains that the distinction between noise and signal is important because it helps us to identify the type of disturbance that we need to reduce or eliminate.