Figure 2.

Influence of the coupling strength ϵ and the learning rate η on the speed of adaptation of standard adaptive frequency oscillators. The yellow shaded area indicates the time during which the external signal is applied. In all cases, the initial intrinsic frequency of the oscillator is f₀ = 4.0 and the frequency of the external unit sine-wave signal is f_ext = 2.0. For the adaptive Hopf oscillator, we choose μ = 1.0. For the adaptive van-der-Pol oscillator, we choose μ = 100.0 (see Methods).