CMOS 2.4 /spl mu/m chaotic oscillator: experimental verification of chaotic encryption of audio

The authors report the first experimental verification of chaotic encryption of audio using custom monolithic chaotic oscillators. We use G/sub m/-C techniques to realise a chaotic modulator/demodulator IC that implements a 3rd-order nonlinear differential equation. This has been fabricated in 2.4 /spl mu/m double-poly technology and includes on-chip tuning circuitry based on amplitude detection. Measurements demonstrate how to exploit the synchronisation between two of these ICs for encrypted transmission.