# rectangular wave

A square wave is a single or periodic oscillation with a step-like rise and fall, with constant positive and negative amplitude and a duty cycle of 50%.

The period of a square wave signal corresponds to the time from the square wave top, the pulse bottom as well as the rise time and the fall time. The square wave signal has a crest factor of "1" and thus the smallest peak voltage in relation to the power. According to Fourier, it consists of a sinusoidal fundamental and further odd harmonics. The amplitudes of the individual harmonics correspond in the spectral representation to the ratio of their number. Thus, the 3rd harmonic has an amplitude that is one third as large as that of the 1st harmonic, i.e. 1/3, the amplitude of the 5th harmonic is 1/5, that of the 7th is 1/7, and so on.