Thesis - Department of Electronic & Computer Engineering

5. Pulse Coupled Winner-Take-AllModel5.1 Basic ModelThe basic pulse coupled WTA model we investigate can be described as follows:τv˙i () t=∑– v i () t + I i + as i () t – b s j () tj≠iwheres i() t = Aut [ ( – t ij– T p)–ut ( – t ij)], represents a fixed width and fixedheight pulse stream, with AT p= θ .U ˙i() t=max( v i()0 t , ), describes a non-leaky integrate-and -fire neuron.U i() tut () is the step function, and { t ij } is the time sequence when U i () t = θ,andis then reset to zero.It is a pulse coupled form of the continuous WTA network described in chapter 2.PFM (pulse frequency modulation) is used as modulation format, where each cell inthe network has an non-leaky IF neuron for activity conversion.The architecture of a single neuron is shown below in Fig. 5.1. And Fig. 5.2 showsthe general communication process when there is no collision involved.34