US Patent 8459103 IDMS signal processing to distinguish inlet particulates

A method for operating a debris monitoring system comprises continuously sensing the passage of particulates through a gas turbine engine to produce a time-domain sensor signal. The time-domain sensor signal is Fourier transformed to produce a frequency domain sensor signal. The frequency domain sensor signal is partitioned into bins corresponding to particulate composition categories. At least one feature is identified within each bin, and is used to determine the amount of particulate flow in each particulate composition category.