The Function of Harmonics

A sawtooth wave has both even and odd harmonics.

Any complex wave shape can be built up from a series of pure sine waves. The main sine wave, called the fundamental, has the same frequency as the complex wave. Other sine waves, called harmonics, appear at exact multiples of the fundamental frequency.

Harmonics

Harmonic sine waves typically have less energy than the fundamental. Each harmonic has a frequency at an exact integer multiple of the fundamental. For example, a complex wave may have second, fifth, and sixth harmonics. To get their frequencies, multiply the fundamental's frequency by 2, 5 and 6, respectively.

Odd Harmonics

Odd-numbered harmonics always make mirror-image wave shapes. The positive and negative parts of the wave have symmetry with each other. Triangle and square waves have only odd harmonics.

Even Harmonics

If the positive and negative parts of a wave don't have symmetry, you can be sure it has even-numbered harmonics. Rectangular pulse and sawtooth waves have mixtures of both even and odd harmonics.

References

• Sample Craze: Phase and Harmonics
• All About Circuits: Mixed-Frequency AC Signals