<P> Square waves are universally encountered in digital switching circuits and are naturally generated by binary (two - level) logic devices . They are used as timing references or "clock signals", because their fast transitions are suitable for triggering synchronous logic circuits at precisely determined intervals . However, as the frequency - domain graph shows, square waves contain a wide range of harmonics; these can generate electromagnetic radiation or pulses of current that interfere with other nearby circuits, causing noise or errors . To avoid this problem in very sensitive circuits such as precision analog - to - digital converters, sine waves are used instead of square waves as timing references . </P> <P> In musical terms, they are often described as sounding hollow, and are therefore used as the basis for wind instrument sounds created using subtractive synthesis . Additionally, the distortion effect used on electric guitars clips the outermost regions of the waveform, causing it to increasingly resemble a square wave as more distortion is applied . </P> <P> Simple two - level Rademacher functions are square waves . </P> <P> The square wave in mathematics has many definitions, which are equivalent except at the discontinuities: </P>

How to find harmonics of a square wave