Before revision: An example of acausal signal processing is the production of an output signal that is processed from another input signal that is recorded by looking at input values both forward and backward in time from a predefined time arbitrarily denoted as the "present" time .
After revision: An example of acausal signal processing is the production of an output signal that is processed from an input signal that was( recorded by looking at input values both forward and backward in time from a predefined time arbitrarily denoted as the "present" time .