CMOS Design of a Chaos‐Based Masking System for Biomedical Signals Applications

ABSTRACT This work shows the development of an electrocardiogram (ECG) data masking system based on double‐scroll synchronized chaotic oscillators. The contribution is devoted to the introduction of a CMOS implementation of a double‐scroll chaotic oscillator, which is designed by taking advantage of the intrinsic hyperbolic tangent‐type characteristic of the operational transconductance amplifier (OTA). The chaotic behavior of the CMOS oscillator is guaranteed by plotting the bifurcation diagram and evaluating the Lyapunov exponents. In this manner, a masking system based on CMOS chaotic systems is designed to protect privacy while transmitting ECG signals effectively. Basically, the chaotic time series is processed to generate pseudorandom signals in a continuous‐time domain. Mathematical modeling and simulation results under a UMC 180‐nm CMOS fabrication process demonstrate that the proposed masking system is well suited to provide hardware‐level security in the chaotic encryption of biomedical signals.