The diagrams depict the power of three added oscillations given by the equation 2sin(2π f⁽¹⁾∙t) + √2 sin(2π f⁽²⁾∙t) + sin(2π f⁽³⁾∙t + 3π/4). In case (a), only two beat frequencies (2 Hz and 4 Hz) with the ratio 1:2 can be generated from the three given frequencies and both of them are visible as fractions of one period in the top chart. In case (b) three beat frequencies (1 Hz, 2 Hz, 3 Hz) are observed. The combination of them results in a different power distribution among the smaller peaks. The perception of such beats is uneven, reminiscent of stuttering and generally less pleasant than in the upper case. Setting the phase angle to zero results in a regular pattern. However, for independently oscillating tone generators (such as organ pipes) the phase angle remains a free parameter.