Square wave harmonics

1. What is square wave harmonics?
2. Does square wave have even harmonics?
3. Why do square waves have harmonics?
4. Which harmonics are produced by a square wave?

What is square wave harmonics?

A square wave consists of a fundamental sine wave (of the same frequency as the square wave) and odd harmonics of the fundamental. The amplitude of the harmonics is equal to 1/N where N is the harmonic (1, 3, 5, 7…). Each harmonic has the same phase relationship to the fundamental.

Does square wave have even harmonics?

A perfect square wave would have no even harmonics. At 1 MHz, the even harmonics are only about 12 dB below the desirable odd harmonics, which means that real information about the DUT may easily be obscured by distortion in the square wave test signal.

Why do square waves have harmonics?

The harmonics of a square wave exist because the rate of change (first derivative) of a square wave consists of very high, sudden peaks; infinitely high spikes, in the limit-case of a so-called perfect square wave. Real physical systems can't follow such high rates, so the signals get distorted.

Which harmonics are produced by a square wave?

Sum of 1st, 3rd, 5th, 7th and 9th harmonics approximates square wave. The end result of adding the first five odd harmonic waveforms together (all at the proper amplitudes, of course) is a close approximation of a square wave.