The astronomical theory and data compared - Ice Ages and Interglacials: Measurements, Interpretation, and Models - page 306

Figure 10.19. Frequency distribution corresponding to the functions in Figure 10.17 .
Figure 10.20. Function F ð t Þ¼ cos ð 1 : 5t Þþ cos ð 2 : 5t Þ .
A final simple example is given in Figure 10.22 , which shows a hypothetical
function that was arbitrarily formed with a quasi-periodic structure. The frequency
distribution corresponding to this function is shown in Figure 10.23 . The principal
frequency is 0.5 per unit time. The period is 2 time units.