Transient signal detection algorithm using order statistic filters applied to the power spectral estimate
AssigneeThe Boeing Company
InventorJames B Baker
Life of this patent
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Abstract
A non-linear, order-statistic filter that is able to detect transients within an ambient signal environment without the transients affecting the setting of the transient detection threshold. The filter obtains a power spectral estimate (PSE) signal for each one of a plurality of predetermined bandwidth portions of the ambient input signal. Specific PSE magnitude values making up the PSE signal are sorted and ordered from smallest to largest. An average PSE magnitude value is obtained for a preselected center range of the specific PSE magnitude values, and this value is used to set the transient signal detection threshold for the filter.
Claims17
A method for forming a filter for detecting transients in an input signal, in which a transient detection threshold of said filter is not influenced by the presence of transients in said input signal, the method comprising:
- determining a power spectral estimate (PSE) signal of at least a predetermined bandwidth portion of said input signal, the PSE signal including background noise forming a noise floor for said input signal, and the predetermined bandwidth portion of said input signal having a bandwidth that is generally in accordance with a bandwidth of a transient signal to be detected;
- using a sorting subsystem and an averaging circuit to analyze said PSE signal over said predetermined bandwidth portion to obtain an average PSE magnitude value for said PSE signal within a preselected portion of said predetermined bandwidth;
- and
- using said average PSE magnitude value for a transient detection threshold, so that said transients present in said predetermined bandwidth portion of said input signal that have a magnitude above said transient detection threshold are detectable without influencing said transient detection threshold.
A method for forming a filter for detecting transients in an input signal, in which a transient detection threshold of said filter is not influenced by the presence of transients in said input signal, the method comprising:
- determining a power spectral estimate (PSE) signal over at least a predetermined bandwidth portion of said input signal, the PSE signal including background noise forming a noise floor for said input signal, and the predetermined bandwidth portion of said input signal having a bandwidth generally in accordance with a bandwidth of a transient signal to be detected;
- analyzing said PSE signal over said predetermined bandwidth portion to obtain a set of time varying, specific PSE magnitude values representing the magnitude of said PSE signal at specific frequencies within said predetermined bandwidth portion;
- using a sorting subsystem and an averaging circuit to determine an average PSE magnitude value from said specific PSE magnitude values using a subset of said specific PSE magnitude values;
- and
- using said average PSE magnitude value for a transient detection threshold for said filter.
A filter for detecting transients in an input signal, in which a transient detection threshold of said filter is not influenced by the presence of transients, said filter comprising:
- a buffer for receiving and temporarily storing a power spectral estimate (PSE) signal representing a power spectral estimate of a predetermined bandwidth portion of said input signal, said predetermined bandwidth portion corresponding to an approximate frequency bandwidth of a transient signal to be detected;
- and
- a sorting subsystem and an averaging circuit, responsive to said buffer, for analyzing said PSE signal and determining an average PSE magnitude value for said PSE signal, and said average PSE magnitude value forming a transient signal detection threshold for said filter, so that said transient signal appearing in said input signal that exceed said average PSE magnitude value can be detected without influencing said transient signal detection threshold.
Dependencies are inferred from the claim text.