In this paper, a design method of neural networks based on VHDL hardware description language, and FPGA implementation is proposed. A design of a general neuron for topologies using backpropagation algorithm is described. The sigmoid nonlinear activation function is also implemented. The neuron is then used in the design and implementation of a neural network using Xilinx Spartan-3e FPGA. The simulation results obtained with Xilinx ISE 8.2i software. The results are analyzed in terms of operating frequency and chip utilization.
Key words : Artificial, Neural , Network, Backprobagation, FPGA,VHDL.