Figure 2.

Cumulative sums of phasors of CEOAE spectrum plotted at three frequencies close to 8 kHz (left) and close to 15 kHz (right). Solid-line circle is circle of radius one; dashed-line circle is a circle ofradius ${\text{CSM}}_{\text{crit}}=\mathrm{0.305.}$ Circle marker at the end of each line segment denotes its CSM across all 32 buffers. Each cumulative sum of phasors labeled by its spectral frequency (in kHz).