Abstract: A circuit interrupting device having an auto-monitoring circuit for automatically testing various functions and structures of the device. The auto-monitoring circuit initiates an auto-monitoring routine which, among other things, establishes a self-test fault during either the positive or negative half-wave, or both, of an AC power cycle and determines whether the detection mechanisms within the device properly detect the self-test fault. An early detection signal indicates that the self-test fault was properly detected without interfering with the normal operation of the detection circuitry and without causing a false trip within the device. Additional functionality of the auto-monitoring circuit permits automatic verification that the device is properly wired, that is, not miswired, and determines whether the device has reached the end of its useful life.

Abstract: A connector for telecommunication systems has input terminals and output terminals arranged in ordered arrays and connected by a circuit having a plurality of conductive paths connecting the respective input and output terminals. The circuit cancels crosstalk induced across adjacent connected terminals by sets of sections. Two of the paths have one set of sections connected in series and spaced from each other between the input and output terminals. Another pair of paths have another set of sections connected in series and spaced from each other between the input and output terminals. Each section of the two sets forms a noise reduction circuit providing a reactive coupling between the respective paths which is greater than adjacent portions of the paths spacing the sections of the two sets.

Abstract: A composite Fresnel lens useful in an infrared passive detection system includes an array of Fresnel lens segments having a given vertical centerline and a curvature of a given radius. The Fresnel lens segments fall in first and second groups. Each Fresnel lens segment in the first group has a long detection range and a width less than one-third of the diameter of an original whole Fresnel lens from which the segment was taken. Also, each lens segment of the first group has a geometrical center located horizontally from the vertical centerline of the array along the curvature of the array through a circumferential distance less than one-fourth of the radius of curvature of the array. Each Fresnel lens segment in the second group has a short detection range less than the long detection range by a predetermined amount and a width less than one-third of the diameter of an original whole Fresnel lens from which the segment was taken.