1. What is an Electronic Signal?
An electronic signal is a way of conveying information using electricity. When we look at a signal’s graphical representation, we can learn about its key parameters, such as voltage and frequency. Electronic signals come in two main types, which are primarily distinguished by the direction in which they flow.
| Signal Type | Key Characteristic |
| Unidirectional Signal | The signal flows in only one direction, which is either entirely positive or entirely negative. An example is a Pulse signal. |
| Bidirectional Signal | The signal alternates between positive and negative directions, crossing the zero point. An example is a Sinusoidal signal. |
For the rest of this guide, we will focus on the pulse signal, a crucial type of unidirectional signal that forms the basis of digital electronics.
1.1. A Closer Look: The Pulse Signal
A pulse signal is a “unidirectional, non-sinusoidal signal” that is created by a “sudden transient change from a baseline value to a higher or lower level value.” When these pulses occur one after another in a continuous series, it is called a pulse train.
The most important takeaway for a learner is how a pulse train represents information. The transitions between a high voltage level and a low voltage level are used to signal a change, while the levels themselves represent the two binary states: ON (a high level) and OFF (a low level).