An impulsive jet is directed against a flat plate. The unsteady pressure is measured at 6 radial positions on the plate using dynamic pressure transducers. The raw signal shown below contains both low frequency and high frequency components making interpretation difficult.

The data can be digitally filtered using the Fourier methods to transform the data into the frequency domain; filter out components greater than 100 Hz; and inverse transform back to the temporal domain. The result, without the high frequencies is easier to interpret.