Figure 2.

Bispectrum magnitude (see equation 3.15) for the signal $𝒮={\sum }_{i=1}^3{A}_i\text{cos}({\omega }_{i}t+{\phi }_i)+\text{cos}(({\omega }_1+{\omega }_3)t+({\phi }_1+{\phi }_3))$ with the frequencies, amplitudes, and phases listed in Table 1.