The Electro-Mechanics Company

John D Osburn

Patrick A Tobola

A transverse electromagnetic (TEM) cell for measuring EM emissions. The TEM cell longitudinal axis is positioned at a fixed angle relative to the horizontal. This fixed angle results in the alignment of the orthoaxis of the TEM cell with the gravity vector. A rotatable platform for supporting an electronic device is positioned inside the TEM cell. The platform is mounted horizontally, and its axis of rotation is vertical (i.e. parallel to the gravity vector). Further, the rotation axis of the rotatable platform intersects the test volume of the TEM cell. Three mutually orthogonal components of EM emissions are measured successively by placing a device on the platform and rotating the device through two 120 degree rotations, thereby measuring three positions. Thus, it is not necessary to tilt the device from a normal, horizontal operating position in order to fully test its EM emissions.

Electromagnetic interference testing apparatus

An improved correlation method that computes E field measurements from voltage measurements produced by a TEM cell. Twelve voltage measurements are taken of radiation emanating from a device under test (DUT) for respective frequencies. The measurements are taken for the six faces of a hypothetical cube enclosing the DUT in both polarizations. Using these 12 measurements, the method identifies the face and polarization of the DUT which produces the highest emanation of radiation at that respective frequency. The method obtains three input voltages from these measurements and determines if the assumption of a dipole gain is adequate. If not, the actual gain is calculated and is used in a 3-input correlation algorithm to obtain more correct data regarding the E field emission of the DUT.

Growing community of inventors

Austin, TX, United States of America

John D Osburn