We implement directly equation 7 by the structure described on figure 2. This implementation is modular since the LIF of order N is deduced from the LIF of order N-1 just by connecting a new module to it. Each module is a quadripole which involves one floating multiplication, one division by a static integer, one addition and one substraction. The complete structure for a LIF of order N counts N modules, and the state of this filter corresponds to the values stored into the N memories. In a delay varying environment, updating the delay costs another addition and two supplementary modules are needed in order to be able to augment the order of the filter.
Figure 2: Modular LIF structure with 
.