The C-Squared System: A General-Purpose Neuron Network Model.

Abstract : This report describes a general-purpose neuron network model referred to as the C-squared (C2) system. The system contains 504 hardware neuron models called syncoders. As the result of an extensive effort to improve these neuron models, five versions (Mod 1 through Mod 5) exist. Regardless of the version, each syncoder circuit board contains two syncoder circuits; and the circuit cards are totally compatible at the board connector interface. The current C2 System contains some syncoders of all versions. The inputs to each syncoder are fixed bias voltages and weighted pulses from other syncoders. These biases and weights are provided by 1,728 sample-and-hold circuits which are set under control of a PDP-8S digital computer. Clearly this provides tremendous flexibility in building complex neuron networks. The ease of constructing such networks is enhanced by providing access to all of the syncoders and sample-and-holds, plus 18 general-purpose operational amplifiers, via three large, removable patch panels. This also allows one to easily change from one complex circuit to another. Discrete components (such as resistors and capacitors) can be connected to the syncoders with special patch cords, modifying the firing characteristics of the individual neuron models. In addition, controls on each syncoder circuit board allow individual neuron thresholds and time constants to be tuned.