Figure 9.

The statistical tests NIST SP800-22 of the pseudorandom number generator (PRNG) that generated by $x_1$, $x_2$, $x_3$, $x_4$ of the system (2) with $\sigma =4$, $\delta =0.5$, $b=2$, $r\in [27,29]$ and for the initial values $(2,1,1,-2)$. (a) Block-Frequency, Discrete Fourier Transform, Frequency (Monobit), Random Excursions, Random Excursions Variant, Serial-1, Serial-2, Linear Complexity, and Longest Run of Ones, respectively; (b) Approximate Entropy, Cumulative Sums (Forward), Cumulative Sums (Reverse), Lempel-ziv Compression, Non-overlapping Template, Overlapping Template, Binary Matrix Rank, Runs, and Universal Statistical.