Nonlinear Filtering Preserves Chaotic Synchronization via Master-Slave System

Figure 5

Both plots are the FT of the state 𝑥₁ of the filter (6) when it is filtering the input signal 𝑢=10sin(𝜔𝑡) for the cases (a) 𝜔=1 and (b) 𝜔=2.

(a)

(b)