Causality
A system is considered causal if the output at time t depends only on the input for times, \({t\le t}_0\), i.e., meaning that the output at a given time does not rely on future times. This property is commonly essential for an analogue physical system to be practical. However, for a digital signal, we can mitigate this constraint by using a non-causal system, which implies attainable feasibility at the cost of processing time and sample storage.