Abstract: A method has been developed and used to non-intrusively interrogate electronic systems in order to determine the system's characteristic response to electromagnetic energy. The method involves subjecting the system under test to two continuous wave signal sources of different frequencies fl and fh and measuring the difference frequency .DELTA.f (fh-fl) emitted from the system under test. The difference frequency, created by mixing action of nonlinear electronic components within the system, is a relative indication of the system's response to fh, fl. By incrementing the two source signals fl and fh by the same frequency step size, .DELTA.f remains constant and is measured for each fh,fl value. The compilation of amplitude measures of .DELTA.f, normalized by the corresponding amplitude measures of fh, fl, provides a relative measure of the frequency domain transfer function of the system under test.

Abstract: A system uses laser optic technology for non-obtrusive monitoring of movements a missile control surface undergoing electromagnetic testing. The system includes a laser source, a detector positioned opposite the laser source, an attenuator assembly positioned between the laser source and the detector, and a recorder for recording data processed by the detector. The attenuator assembly consists of a framed translucent gray scale shaded window mounted on a block member, which in turn is mounted to the missile control surface. The control surface is a pivotally mounted canard member on the missile body. Generated laser beams project onto the gray scale shaded window. The gray scale shading affects the intensity of the directed laser beams (darker areas attenuate more light and lighter areas allow more light to pass through).

Abstract: A phantom test cell and method for testing the response of a cardiac pacemaker to electromagnetic fields. The phantom comprises a substantially rigid shell which has a torso-like section and two leg-like appendages. The entire shell is filled with a tissue-equivalent material, which in one embodiment represents an upper bound approximation of human whole body averages. The phantom's torso is equipped with a plurality of access ports to which a current probe containment vessel may attach when immersed in the tissue-equivalent material. The containment vessel houses a current probe and flooded tube through which an implanted pacemaker's leads may pass, allowing induced currents to be monitored. In operation, lead current measurements are taken within the phantom and are normalized using measurements taken without the presence of a phantom. A transfer function is computed by taking the ratio of the induced current measured and a reference E-field and/or H-field measurement.