revised: 01/18/99; 01/16/00; 09/01/01

# CHAPTER 2 — Analog and Binary Signals

Everyone knows that computers are "digital" and that they use "binary" numbers. You probably have some idea of what these terms mean. But we need to be clear about their precise meaning and to be clear about why computers are digital.

#### Chapter Topics:

- Binary signals.
- Analog signals.
- Advantages of Binary.
- Bits.
- Noisy signals.

Study these topics carefully if you want to know what is really going on with computers.

Note: This is a copy of chapter 2 of the on-line Java tutorial located at http://chortle.ccsu.edu. If some of this is new to you, then you might benefit from a visit to the first four chapters of that tutorial.

### QUESTION 1:

Why is a digital wristwatch called "digital?"