State space modeling of non-causal impulse responses

In this short paper we present a state-variable model for a non-causal impulse response (IR). The IR is split into causal and anti-causal parts. The anti-causal part is then converted into an equivalent causal state-variable model. The order of the complete system is 2n, where n is the order of the original causal portion of the two-sided IR. Because n can be kept quite low (e.g., 2 or 3) the overall order for our complete system is also quite low. Simulations, as well as analysis, demonstrate that our state-variable model is equivalent to the original two-sided convolutional system model.