Nature’s autonomous oscillators

Abstract

Nonlinearity is required to produce autonomous oscillations without external time dependent source, and an example is the pendulum clock. The escapement mechanism of the clock im-parts an impulse for each swing direction, which keeps the pendulum oscillating at the resonance frequency. Among nature's observed autono-mous oscillators, examples are the quasi-bien-nial oscillation of the atmosphere and the 22-year solar oscillation [1]. Numerical models si-mulate the oscillations, and we discuss the non-linearities that are involved. In biology, insects have flight muscles, which function autono-mously with wing frequencies that far exceed the animals' neural capacity. The human heart also functions autonomously, and physiological arguments support the picture that the heart is a nonlinear oscillator.