In audio, it is common to work with signals that were originally created by acoustic vibrations and captured by a microphone.
In other cases, it can be helpful to work with signals that were created as digital information. Any time a signal is created directly as digital information (or also as electricity), that signal can be described as a synthesized signal. In other words, synthesis is the process of creating a signal.
The nice thing about working with synthesized signals is we can create them to have desirable characteristics. This can be helpful when using “test signals” to analyze various audio effects (i.e. signal processing methods).
There are several common synthesized signals used in audio applications. This section demonstrates the synthesis of each type of synthesized signal and presents the interesting characteristics about each one.
There are many other advanced methods of signal synthesis that will be explored in other sections. For now, let’s start by using basic mathematical functions. First, let’s consider a category of signals which are periodic.