US Government As Represented by the Secretary of the Army

Vincent J Ellis

Bruce T Benwell

Thomas J Bock

David J DeTroye

Charles L Brown

Harold E Boesch

Dave DeTroye

An electromagnetically transparent fluidic operator for adapting a conventional, mechanically operated electric switch to remote, fluidic operation includes a non-metallic housing for being rigidly attached to the electric switch with a chamber in the housing aligned with a mechanical actuator of the electric switch and a non-metallic, expandable reservoir mounted by the housing. The reservoir includes a nipple rigidly attached to the housing and a deformable diaphragm forming a seal with the nipple and being disposed in the chamber close to the mechanical actuator. The reservoir is pressurized with fluid from a remote location causing the diaphragm to deform and the reservoir to expand thereby applying a positive pressure or operating force against the mechanical actuator to operate the electric switch. A method of adapting an electric switch for remote, fluidic operation includes the steps of rigidly attaching the housing to a selected electric switch such that the chamber in the housing is aligned with the mechanical actuator, positioning the diaphragm in the chamber close to the mechanical actuator, rigidly attaching the nipple to the housing, establishing a seal between the nipple and the diaphragm to form a fluid-tight reservoir and supplying fluid to the reservoir to deform the diaphragm and apply the operating force against the mechanical actuator.

Electromagnetically transparent fluidic operators for remote operation

An acoustic impulse source has been developed and used to simulate the high coustic output of detonation driven acoustic sources. While detonation driven acoustic sources are capable of producing large acoustic signals (&gt;160 dB) at 10s and 100s of meters from the source, their laboratory use is limited due to the combustion byproducts. The present invention is capable of reproducing the downrange detonative source acoustic signals (170 dB) at short range, on the order of 1 meter, without noxious or large thermal byproducts. The present invention relies on the plasma formation resulting from electrical arc discharge in air to generate thermal impulses and the resultant acoustic signals. Utilizing multiple plasma channels and timing control of the formation of said channels, the present invention achieves increased efficiency and the ability to tailor the acoustic output signal to match the desired detonation source characteristic output.

Multiple plasma channel high output variable electro-acoustic pulse

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. The present method is performed with the test equipment in total isolation from the system under test and may be used to quickly and cost effectively identify those frequencies to which the system under test may be susceptible.

Two tone test method for determining frequency domain transfer

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). Accordingly, data is obtained from tracking the different shades of the light intensities which are directly related in synchronization with the movements of the canard member of the monitor assembly. The resulting intensity data is detected and measured by the detector and then processed by the recorder. Thus, as the control surface moves, the recorded data provides a basis for determining recognition characteristics with respect to the missile control surface, such as (1) the direction of the movement, (2) the distance of the movement, and (3) the speed of the movement.

Laser-optic missile control surface monitor

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. A source of interest is then convolved with the transfer function to determine what the induced current would be in an implanted pacemaker. In one embodiment, the induced current which is arrived at analytically is then physically injected into a cardiac pacemaker outside the test phantom to reproduce EMI effects.

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Stafford, VA, United States of America

Vincent J Ellis