On the realization of NPN-only log-domain chaotic oscillators

Two new chaotic oscillators with double-scroll dynamics based on the log-domain circuit-design technique are presented. As the circuits operate in log domain, they are suitable for low-voltage, high-frequency operation. The important key parameters of the oscillators are electronically tunable, thus, they are well suited for integrated circuit implementation. Furthermore, the circuits do not employ any PNP transistors, hence they can be implemented in cheap bipolar processes, which do not offer high-quality vertical PNPs. Experimental results verifying the feasibility of the circuits are given.