1. A cellular neural network for implementing a so-called Chua's circuit, the cellular neural network comprising: a first cell; a second cell coupled to the first cell; and a third cell coupled to the second cell, wherein each cell includes a first input terminal to receive a respective first reference signal, a second input terminal to receive a respective second reference signal, and a state terminal, wherein one of the cells is of a first type and the other cells are of a second type, wherein the first type and the second type are different; wherein at least one of the cells includes an internal node and an amplifier stage connected between one of the input terminals and the internal node, wherein the amplifier stage has dynamically programmable gain.