This paper addresses the design of two neural network
systems based on the use of pulsing neurons. Each neuron is
built as a simple voltage controlled oscillator (VCO) whose
control voltage makes the circuit to oscillate or not. The
interconnecting synapses between neurons are made with
programmable transconductance amplifiers. The weight of
each synapse is represented by the transconductance gain of
the amplifiers, and is externally adjustable for each synapse.
Using this technique a 5-neurons Hopfield network and a 6-
neurons BAM network were built and tested, using standard
2km double-metal, double-polysilicon CMOS (MOSIS)
chips.