Nonboolean Pattern Recognition Using Chains of Coupled CMOS Oscillators as Discriminant Circuits

Networks of weakly coupled oscillators are special cases of Hopfield networks and as such may be used in building physical systems capable of associative memory recall and pattern recognition. However, the existing architectures are not suitable for hardware implementation mainly due to the complexity of required couplings between the oscillators. In this paper, we propose an alternative way of using coupled oscillators in what we call “discriminant circuits” in analogy to the concept of “discriminant functions” in the field of artificial intelligence and machine learning. The main advantage of our system is in the simplicity of its architecture, which relies only on local couplings between adjacent oscillators. Using this architecture, we design a network of coupled CMOS oscillators as the core of a physical non-Boolean pattern recognition engine. The simplicity of the proposed circuit makes it readily implementable on any standard CMOS technology.