Weak signal detection by small-perturbation control of chaotic orbits

We have developed a method of detecting extremely weak signals using fundamental principles of chaotic dynamics. We calculate the time-dependent coupling of the disturbance signal to the stable and unstable manifolds of the system and derive a relationship between the disturbance and the error on the Poincare surface of section, thus relating the disturbance signal to the perturbations needed to control a periodic orbit. We demonstrate the algorithm in a computer model of a chaotic system and discuss its implementation in high-frequency devices.