A CMOS Analog Chaotic Oscillator for Signal Encryption

This paper presents an innovative application for analog integrated circuits, based on nonlinear signal processing concepts. We report the first monolithic realization of a chaotic continuous-time nonlinear dynamic system. It corresponds to a third order differential equation known as the Chua´s equation, and has been implemented using nonlinear gm-C techniques in a 2.4¿m CMOS technology. Measurements demonstrate the possibility to engineer analog integrated circuits capable of generating controllable continuous-time chaotic signals. This opens new vistas for the exploitation of analog circuits in signal processing systems. In particular we show how to exploit the synchronization between two of the herein reported oscillators for the issue of signal encryption.