Beats

In this applet, two waves with different frequencies are superposed one on another. Vary the two frequencies, f₁ and f₂, between 1 und 100 Hz and see the corresponding beat pattern emerge. The beats are something such as pulses in which the amplitude of the basic wave changes. The frequency of the base wave is given as the average of both superposed frequencies, so it is approximately equal to both this frekvencies. On the other hand the frequency of beats is much more lower - is given as difference of partial frequencies.