New chaotic third-order log-domain oscillator with tanh nonlinearity

Abstract

Log-domain filters are an intriguing form of current-mode circuit in which the large-signal exponential current-voltage relationship of the bipolar junction transistor is used first to convert the input currents to logarithmic form, where the analog processing takes place, and then to map the output voltage waveforms back to the current domain at the end of the filtering process. The log-domain filter synthesis technique can be extremely useful in the design of chaotic oscillators suitable for low-power high-speed integrated circuit implementations. This paper presents a new third-order log-domain chaotic oscillator, which may be used in chaos-based communication systems. Although the design of the proposed oscillator stems from a known nonlinear dynamical system which may be subject to chaotic oscillations, its dynamics differ from those of the model and, as a result, are worth investigating.