US Patent 7248985 Acoustic signature testing for electronic, electromechanical, and mechanical equipment

A method for testing a unit is described where the unit includes one or more of electrical, electronic, mechanical, and electromechanical components. The described method includes applying at least one stimulus to the unit, receiving sound emissions from the unit, converting the sound emissions into one or more acoustic signatures, comparing the acoustic signatures based on the received emissions to stored acoustic signatures expected as a result of the at least one stimulus, and determining a status for the unit based on the comparisons.