How would you generate this type of wave form?
Try a suitably parameterized function of form:

$$f(t) = \operatorname{clip}\big(a_0\sin(f_0 t) + a_1\sin(f_1 t)\big),$$

where $t$ is time, $f_0$ and $f_1$ are the frequencies and $a_0$ and $a_1$ the amplitudes of two sine waves, and:

$$\operatorname{clip}(x) = \left\{\begin{array}{ll}-1 &amp;\text{if } x &lt; -1\\x &amp;\text{if }-1 \le x \le 1 \\1 &amp;\text{if } x &gt; 1.\end{array}\right.$$

You don't show the scale of the data so the bounds $-1$ and $1$ might be of wrong absolute value. I assumed that the data is zero-centered so there is no zero frequency (bias) term and the bounds look symmetrical in your graph.