Sine Wave

Sine Waves is the output of the sine function.

It is best illustrated by the following animation. A vector change it's angle over time, and the sine function is the Y-axis output:

The frequency of the result is expressed in Hz (Hertz) - number of waves per second. So 1 Hz is one full revolution of the vector in the circle every second. When calculating this one would usually have a set number of samples every second - for example 48000 (just about enough to cover the spectrum of audible sounds). In this case, the frequency can be expressed as an angular speed - angular increase every sample.