Abstract: Apparatus and method are provided for releasably connecting to a base or assembly a box or the like such as an electrical module. Opposite mutually parallel sides of the box are each provided with a pair of projections having distal heads wider than their exposed shafts. The base or assembly is provided with a pair of parallel plates or angle irons sufficiently separated to accommodate the box and each provided with a pair of openings positioned and configured to receive and retain one of the projections. Preferably, each such opening has a right angle bend. For mounting, the box is placed on the base or assembly between the two plates or angle brackets such that each of the projections enters one of the openings. A right angle bend in the opening permits the opening to releasably retain that projection. At least one of the openings on each side is provided with a latch and a bail configured to releasably engage such a projection when the projection is disposed in the opening.

Abstract: This is a Mode S radio frequency transmission system with coordinated use of a rotating directional antenna and omnidirectional antennas. A software-implemented prefilter both processes messages destined for aircraft equipped with Mode S datalink capable transponders, and prevents any uplink message transmission to a transponder from coinciding with the once-per-scan surveillance interrogation from the rotating antenna as well as any datalink interrogations specified for transmission through the rotating antenna.

Abstract: A system and method is disclosed for feedback velocity control of a D.C. motor. The system includes a motor (30) which is represented by its circuit equivalent--a series combination of an inductance (32), a resistor (34) and a back EMF source (36). The drive to the motor (30), supplied by a controller, is periodically inhibited by timing logic (22) and AND gate (20). Once the inductive transient decays via clamping diode (38) such that the motor current is zero, switch (40) is closed and the internally generated motor voltage is sampled by a capacitor (42). A/D converter (44) transforms the sampled value to a digital value and sends it to the controller. The controller compares it to a predetermined desired value then makes the necessary adjustments to the drive signal.

Abstract: Flat mail pieces of intermixed sizes and thicknesses are received and distributed to separately arranged storage compartments. Each such compartment contains special features and functions which ensure smooth entry of incoming mail, maintain the facing and orientation of received mail pieces, readily permit stack accumulation, and readily enable release of a full stack from the storage compartment. A vertically-mobile stack support plate maintains a relatively short but constant drop distance for all mail pieces entering the stacking compartment. To transfer a stack of mail, the stack is stripped off its support plate and onto a bed of rollers by lateral movement of the storage compartment away from the support plate. After a tray container has been positioned to accept the stack of mail, the bed is rolled out from beneath the stack, gently transferring the stack onto the bottom of the tray.

Abstract: A wave reflecting dish is constructed to provide a one piece unit having a hollow, watertight region between a first external surface having a paraboloidal contour and a second external surface which includes a base. Heater elements are positioned in the hollow region on a surface opposite the first external surface. Insulating material cover the heater elements and the hollow region is filled with a foam material. Snow, ice, and water drainage from the first surface is provided through a hole which extends through the unit from the first surface to the second surface. Provisions for mounting wave emitting and receiving apparatus are provided within the first surface. Attachment pads for mounting the dish on an external structure are provided on the base.

Abstract: A power amplifier includes a plurality of signal amplifying stages. An amplitude compensator positioned prior to the ultimate signal amplifying stage equalizes the signal amplitudes in the frequency band of interest to provide a substantially flat frequency response. Fail-soft operation is established by providing switchably redundant amplifiers. When an operating amplifier is detected as failing, automatic switching is performed to replace the failing unit with an identical unit to maintain amplifier operation. High-power amplification is accomplished by splitting a preamplified signal into a plurality of signals, amplifying the lower level signals so obtained, and then recombining the amplified signals.

Abstract: A backstop of the "venetian blind" type and contains a set of angled louvers to deflect projectiles safely. The present invention provides a system of modules whereby a backstop may be constructed across a wall of any width. The backstop modules themselves are made in a number of standardized widths, most preferably about 36 inches (0.91 m), 48 inches (1.22 m), and 60 inches (1.52 m) wide. Using various sets of these modules, any width can be filled in to the nearest foot, i.e., a maximum gap of about six inches remains between the end modules and an adjacent wall surface. These remaining gaps are preferably filled in using a sliding, angled wall plate that accommodates gaps between about zero and six inches. The visible flat edges of plates that form the sides of adjacent modules and the plate against the floor are ricochet hazards, and thus are also preferably provided with angled deflectors.

Abstract: A low radar cross section lens antenna having high gain is disclosed. A spherical lens having a dielectric radial gradient focuses planar RF energy coupled thereto onto a focal point on the surface of a lens located diametrically opposite from the first intersection of the plane wave and the lens. The lens partially encloses a wedge shaped RF absorbing portion having the edge of the wedge passing through the center of the lens. The lens is partially surrounded by a second RF absorbing portion having a bowl-like shape. An antenna feed having its aperture located adjacent the surface of the lens is mounted to rotate about an axis lying substantially along the edge of said wedge shaped absorbing portion. Elevation rotation means is provided to rotate the feed antenna within a slot contained within the second RF absorbing portion.

Abstract: Apparatus and method are provided for receiving a flow of packages such as parcels or bundles, dividing it into plural streams for easier singulation, singulating each such stream, and delivering the produced packages one at a time to a user, each stream being provided to a different user. Downstream sensors are used to control a deflector which in turn divides a received flow of packages into multiple such flows and apportions the received packages among the two output flows. Singulation of each such output flow is accomplished by a plurality of inclined belts which each moves a received package upward and over its peak to drop for entry into the next stage downstream, thereby singulating the received flow in stages. These belt stages are individually controlled by further downstream sensors and motors which prevent movement of upstream such belt(s) if one or more packages, indicating a flow blockage, is sensed downstream.

Abstract: A backstop and bullet trap are disclosed that provide access from the front so that spent projectiles can be removed without requiring a crawl space along the side or rear of the backstop, thereby permitting maximum use of the interior space into which the backstop and bullet trap have been installed. The present invention discloses a backstop that has a removable panel on the lower edge of a lower deflector. Preferably the lower panel overlies the lower deflector and is hingably connected to the floor or near the floor. In a preferred embodiment, this hinge connection is provided by resting the lower edge of the removable panel in a recess in the floor. In this embodiment, the removable panel presents an angled deflector surface to the shooter and no additional floor deflectors are required. Methods of removing projectiles from a backstop and bullet trap are also disclosed.

Abstract: Apparatus and method are provided for determining and indicating if certain types of circuit failures have occurred in a D.C. motor circuit such as a locked rotor condition, a short-circuit or an open circuit. The method includes the steps of, and the apparatus involves applying a voltage to two leads of the D.C. motor sufficient to cause motor rotation, determining if flyback exists, determining if back EMF exists, and, finally, if a back EMF does not exist and flyback does exist then indicating a locked rotor condition. However, if a back EMF does not exist and flyback does not exist then an indication is provided that either an open-circuit or short-circuit condition exists. The same apparatus and method can be used with a voltage not sufficient to cause motor rotation, although given this limitation only flyback can be detected, so that only an open-circuit or short-circuit condition can be indicated.

Abstract: Apparatus and method are provided for receiving a flow of packages such as parcels or bundles, dividing it into plural streams for easier singulation, singulating each such stream, and delivering the produced packages one at a time to a user, each stream being provided to a different user. Downstream sensors are used to control a deflector which in turn divides a received flow of packages into multiple such flows and apportions the received packages among the two output flows. Singulation of each such output flow is accomplished by a plurality of inclined belts which each moves a received package upward and over its peak to drop for entry into the next stage downstream, thereby singulating the received flow in stages. These belt stages are individually controlled by further downstream sensors and motors which prevent movement of upstream such belt(s) if one or more packages, indicating a flow blockage, is sensed downstream.

Abstract: Apparatus and method are provided for receiving a flow of packages such as parcels or bundles, dividing it into plural streams for easier singulation, singulating each such stream, and delivering the produced packages one at a time to a user, each stream being provided to a different user. Downstream sensors are used to control a deflector which in turn divides a received flow of packages into multiple such flows and apportions the received packages among the two output flows. Singulation of each such output flow is accomplished by a plurality of inclined belts which each moves a received package upward and over its peak to drop for entry into the next stage downstream, thereby singulating the received flow in stages. These belt stages are individually controlled by further downstream sensors and motors which prevent movement of upstream such belt(s) if one or more packages, indicating a flow blockage, is sensed downstream.

Abstract: Apparatus and method are provided for determining indicating if certain types of circuit failures have occurred in a D.C. motor circuit such as a locked rotor condition, a short-circuit or an open circuit. The method includes the steps of, and the apparatus involves, applying a voltage to two leads of the D.C. motor sufficient to cause motor rotation, determining if flyback exists, determining if back EMF exists, and, finally, if a back EMF does not exist and flyback does exist then indicating a locked rotor condition. However, if a back EMF does not exist and flyback does not exist then an indication is provided that either an open-circuit or short-circuit condition exists. The same apparatus and method can be used with a voltage not sufficient to cause motor rotation, although given this limitation only flyback can be detected, so that only an open-circuit or short-circuit condition can be indicated.

Abstract: Apparatus and method for communication of data from a holder to a customer or other requester of such data. The requester identifies to the holder a specific data product or other piece of data known to be held by the holder. The holder responds with a message acknowledging that request and providing at least one characteristic of the data so requested. The requester utilizes the information contained in that acknowledgement to determine whether the requester wants the data that it has so identified. The requester then informs the holder, based on that determination, whether the requester still wants the holder to provide that data to the requester. In response to that message from the requester, the holder either transmits the requested data, or awaits a further request from that requester, or terminates the communication. This apparatus and method further includes a provision for verification of proper communication of requested data.

Abstract: Apparatus and method synchronize one or more digital clock signals from separate oscillators, to another clock oscillator via a common non-continuous signal, and provide error signals to indicate when one or more oscillators are out of tolerance.

Abstract: Commutation switches for electronically scanning cylindrical arrays are disclosed. One embodiment reduces the number of transfer switches needed in a commutation switch by utilizing the commutation inversion property inherent to transfer switches having a binary number of input and output ports. A second embodiment having inversion capability provides a transfer switch with non-binary number of input and output ports. Commutation switches employing transfer switches of the second embodiment exhibit reduced complexity over the prior art and provide lower signal loss than that achievable with commutation switches of the prior art.

Abstract: Broadband, monolithic, planar m.times.m and m.times.n transfer switches with diode switching elements are disclosed. Symmetry of the switches maintain equal insertion amplitude and phase performance. Compensation of phase unbalance caused by diode parasitic capacitance is provided by inductors serially coupled between the diodes and the input and output terminals of the transfer switch. Stripline transmission lines are utilized and isolation between the transmission lines is provide in regions of stripline cross over in the plane.

Abstract: Apparatus and a method for increasing the speed of acquisition of PN coded signals includes a novel PN code clock extraction circuit which is coupled in parallel to a code tracking loop and acquisition loop of a PN receiver of the type having a replica PN code generator which is slip controlled to synchronize with the received PN coded signals. The novel PN code clock extraction circuit detects the clock transition of the received PN coded signals and synchronized the replica PN code generator clock transition signals so that there is no misalignment during acquisition. A switch control in the acquisition loop circuit senses the synchronization of the replica PN code generator transition and the received PN code transition and disconnects the PN code clock extraction circuit after synchronization of clock transition and before acquisition of the PN code so that the acquisition loop detects the PN code synchronization with a full strength signal.

Abstract: Apparatus for rapidly acquiring a high performance gain long PN code having a preamble header in real time includes appratus for rapid acquiring and tracking a short PN code in said preamble header and further includes apparatus for demodulating and tracking a long PN code which follows said preamble header. After acquiring the short PN code, the short PN replica code is applied to the long code demodulation and tracking apparatus. The short PN code is employed to synchronize the long code demodulation and tracking apparatus by detecting the time of occurrence of a sync word in said preamble header and is employed to generate a switch point signal and switch from a short PN replica code to a long PN replica code at the input to the long code demodulation and tracking device in real time.