Abstract: A dual-section spatial modulator transmitter consists of a collector surrounding a source of radiation to collect the energy from the source and form it into multiple beams. The collector is configured in two sections, a rotatable section and a stationary section such that spatial modulation is obtained by rotating only the rotatable section.

Abstract: An improvement to graphics pen plotters including a pen gripping mechanism for gripping a cylindrical bodied pen in a generally vertical orientation for sensing the presence and type of a pen in the gripping mechanism with a single sensor. There is a multi-channel sensor adapted for producing and sensing a plurality, "n+1", of parallel light beams disposed one above the other to produce a binary number at an output thereof indicating the ones of the light beams sensed by the sensor. The sensor is disposed to shine the light beams at a position past which the pen is moved by the gripping mechanism. There is also a cylindrical reflective surface disposed about a portion of the body of the pen so as to be struck by the light beams when the pen is being gripped by the gripping mechanism at the position and reflect the light beams back towards the sensor to be sensed thereby.

Abstract: A method and apparatus for routing, holding, and hiding cables associated with electronics devices. The preferred embodiment is an extrusion for application to a surface of an electronics device or incorporation into the framework thereof defining a groove capable of routing, holding, and hiding the electrical cable(s). The extrusion has a cross-section comprising a plurality of sides connected to one another to define a desired shape for the extrusion. A pair of the sides have a generally V-shaped orientation with respect to one another thereby forming a longitudinal slot in the extrusion capable of containing the cable therein. The slot-forming pair of sides each includes opposed portions comprising a plurality of adjacent V-shaped segments thereby forming opposed longitudinal teeth in the sidewalls of the slot capable of releasably gripping a cable disposed in the slot.

Abstract: A plurality of switched voltage sources (10, 10', 10") apply charge to a sheet of paper (16) by way of respective sets of styli (12, 12', 12"). To print a dot when toner is subsequently applied to the paper, the voltage source (10) deposits charge on the paper (16) by applying a high voltage, and its voltage returns to ground when it is to avoid leaving a mark. In order to avoid the image degradation that results from the proximity of an unenergized stylus to an energized one, a zener diode (14) is interposed between the switched voltage source (10) and its respective styli (12). By virtue of stray capacitance (C.sub.s) between the styli (12) and ground, the potential of the styli does not return completely to ground when their respective voltage source is switched off. Instead, it returns only to the zener voltage, and this reduces the image degradation that the presence that the unenergized styli would otherwise cause.

Abstract: An improvement to position digitizing devices wherein sensed response voltages caused by the interaction of a movable instrument relative to conductors beneath a planar surface are converted to digital form and digitally processed to determine instrument position. An integrating voltage to frequency converter is used to produce a frequency with a correspondence to the voltage applied to it. By counting the frequency for a defined length of time, a resultant count is obtained which also corresponds to the applied voltage. By varying the counting period under microprocessor control, acquisition rate and resolution can be varied over several orders of magnitude without changing circuit components. The digitizer includes conductive elements disposed across the digitizing surface and incorporated into an instrument for producing an analog voltage signal having a DC component related to the position of the instrument on the digitizing surface.

Abstract: A radiation system consists of a compound collection/beamforming system, surrounding a source of radiation, including an elevation collector/beamformer shaped as a compound parabolic concentrator and an azimuth collector/beamformer shaped so that tangential rays emanating from the source will be collected and formed into a beam of a predetermined design, and a modulator for alternately blocking and unblocking the beam from the compound collection/beamforming system.

Abstract: An electromagnetic dispersive delay line (10) includes a dielectric strip (28) as well as a coupler (24, 34, 36, and 38) for launching surface electromagnetic waves into the dielectric strip. The upper surface of the dielectric strip (28) is left exposed to the air in order to provide an interface with a lower-permittivity medium of propagation. This permits a surface-electromagnetic-wave propagation mode. The thickness of the dielectric strip (28) is varied along its length so as to result in a linear relationship of delay to frequency throughout a predetermined frequency range. Preferably, a conductive strip (26) spaced from the dielectric strip extends along the surface-wave propagation path in the region occupied by the evanescent field external to the dielectric strip (28). This conductive strip (26) modifies the phase relationships between the electric and magnetic fields in the evanescent-field region so as to cause some of the power transmission to occur outside of the dielectric strip.

Abstract: A device for repeatably and accurately testing an antenna coupler of the type used to connect a test antenna adjacent an onboard antenna of an aircraft to inject a test signal into the aircraft's onboard radar system to test its continuity. A base member is provided with the verification antenna mounted therein. Alignment tabs are provided on the base member for receiving points along the periphery of the antenna coupler. In a preferred embodiment, the base member is mounted inside the lid of a packing case for carrying a plurality of antenna couplers and individual alignment tabs are provided and provided with indicia for properly aligning each of the antenna couplers over the verification antenna. In another embodiment, retractable shielding is provided for electromagnetic shielding of the base member, verification antenna, and antenna coupler during operation.

Abstract: A microstrip tee-fed slot antenna is made up of only a single printed circuit board having the tee feed and slot on the front side and a microstrip transmission line feed on the back side. A plurality of holes in the board surrounding the slot are electrically connected front to back to provide the antenna cavity. Since only a single board is used having all of the components of the antenna on either side, no disassembly is required to add to or modify the elements of the antenna.

Abstract: A system (34) for determining deviations in the state of motion of a projectile (10) from its intended state includes a comparison module (38) that receives the outputs S of a sensor array (36). The comparison module (38) converts the sensor outputs to a measurement vector Z.sub.m and computes the deviation of this measurement vector from an intended measurement vector Z.sub.0 received from a control system. The comparison module (38) then determines the difference E.sub.Z between this measured deviation and the deviation predicted by a Kalman filter (44, 46). In generating the measurement vector Z.sub.m from the outputs of the sensor array (36), the comparison module (38) "de-spins" the array outputs in accordance with the output of a phase reference (42), whose purpose is to indicate the phase with respect to gravity of the spin of the projectile (10) about its longitudinal axis.

Abstract: A pen type sensor for use in a graphics pen plotter wherein plotter pens are moved along a pre-established path between a pen holding area and a plotting area for reading a plurality of vertically oriented reflective indicia positions thereon to create a binary logic output signal representative of the pen type. There is a hollow body member having a pair of angled front surfaces. Light emitting apparatus is associated with one of the pair of angled front surfaces for directing a light beam to simultaneously strike the indicia positions at a point on the path of pen movement. A plurality of light detectors are associated with the other of the pair of angled front surfaces for receiving on respective sensing surfaces thereof the light beam as it is reflected by reflective indicia on a pen at respective ones of the positions and for creating respective bi-stable output signals reflecting the presence and absense of reflected light on the sensing surfaces.

Abstract: Apparatus for accurately raising and lowering the pen and for generating a positional signal for control use in a graphics plotter having a penholding mechanism slidably and rotationally mounted on a beam for longitudinal positional movement along the beam and rotational movement around the beam to affect raising and lowering of a pen held by the penholding mechanism under the control of plotter control logic. There is an actuator rod disposed parallel to the beam for rotational movement about a longitudinal axis. A spring biases the penholding mechanism to the raised position. A ball bearing linkage is provided for smoothly and slidably linking the actuator rod to the penholding mechanism so that as the penholding mechanism is smoothly moved longitudinally along the beam, rotation of the actuator rod will cause corresponding rotation of the penholding mechanism towards the lowered position.

Abstract: In a graphics plotter having motor control logic for controlling a motor employed in the process of drawing a series of vector lines comprising a plot, an improvement to the logic for applying optimum control of the motor. The length of each next vector to be drawn is first calculated. The logic for controlling the motor is then self-adjusting as a function of whether the next vector line to be drawn is a short-length vector less than a pre-established length or a long-length vector longer than said pre-established length.

Abstract: An assembly for mounting components to a microwave circuit, using plated through bore holes that extend from the ground plane of the circuit through the insulating substrate to the surface on which the components are mounted. The components have a conductive outer surface that functions as its ground plane. This surface is in electrical contact with the plated through bore holes, creating a uniform ground plane between the microstrip circuit and the component. The insulating dielectric can be provided with a recess in which the component can be housed. The base of the recess can be plated and the plated through bores connected between the cavity plating and the ground plane. The component can then be positioned inside the recess so its ground plane is in contact with plating so as to form a uniform ground plane between the circuit and the component.

Abstract: An adcock DF-on-the-fly type direction finding system employing a beam forming dispersive delay line (BFDDL). A square array of four elements A1, B1, C1, and D1 with A1, C1 and B1, D1 being the diagonal pairs is used to input signals to combiner, shifter and summer elements to produce signals representing S.sub..phi. =A1+B1+C1+D1 and S=(B1-D1)+[(A1-C1) shifted -90.degree.]. S.sub..phi. and S are input to the BFDDL which produces output signals sampled from the output spatial interference pattern of the BFDDL at 90.degree. intervals. The output signals from the BFDDL are used to calculate the arrival of the signal of interest as being substantially equal to the phase shift between S.sub..phi. and S.

Abstract: Methods and apparatus for forming an electrostatic printhead. The basic printhead member if formed by casting an insulating material around a plurality of side-by-side spaced wires. One side of the insulating material and the wires are cut off to form a printhead face. The other side of the insulating material and the wires are cut off to form an attachment face with the wire ends exposed. A printed circuit board having electrical contacts along the edge is positioned adjacent the exposed wire ends of the attachment face and the wire ends are wire bonded to the contacts. In one embodiment, there are two printed circuit boards positioned on either side of the attachment face and then folded together following the wire bonding. In another embodiment, the attachment face is formed as ledges having the exposed ends of the wires cut as rectangular pads for more area of attachment and the insulating material is attached to the edge of a single printed circuit board.

Abstract: A test system for microwave circuits such as employed in aircraft wherein a plurality of antennas are connected to a single processor whereby the continuity of the antennas and connectors between the antennas and the processor can be determined. A test signal is applied to the various antennae of the aircraft and the return signals therefrom received by a test antenna disposed in conjunction with a low-loss coupler from outside of the aircraft. An automated test circuit provides for inputting an identifier of the antenna and circuit portion being tested, and for determining the fault location within the circuit as a function of the circuit portion under test and the distance to the fault; and for displaying the fault location within the circuit. In one embodiment, the low-loss coupler includes the use of a plurality of test antennas in combination with a divider circuit connected to the test antennas by transmission lines.

Abstract: A digitizing tablet (10) has common return lines (24, 25, 26, and 27) that tend to suppress sensing of the spurious signals induced in them when the digitizer probe (12) approaches the edge of a digitizing area (14). Each return line includes a connection segment (36) and a compensation segment (40), which extend in antiparallel along the edge of the digitizing area (14). The compensation segment (40) is spaced farther from the digitizing area than the connection segment (36) is so that it is only half as sensitive as the connection segment to probe signals. However, since only half of the emf induced in the connection segment (36) is coupled to the circuitry (22) for processing the induced signals, the signals induced in the return lines tend to cancel.

Abstract: A convertible platen for use in a graphics plotter to allow its selective use as either as either a cut paper plotter or a roll paper plotter. The platen is formed from a specially designed aluminum extrusion and a pair is mounted with one on either side of the drum of a drum plotter between the drum and the supply/takeup rollers. The platens can be raised and held adjacent the drum and spanning the vacuum columns in the plotter to create a table having curved outer edges to support cut paper. They can be released and dropped into the vacuum columns whereby they lie against the outer surfaces and form the upper inner wall with curved upper edges over which paper smoothly is guided between the vacuum column and the supply/takeup rollers.

Abstract: An easily adjustable and automatically aligning pinch roller assembly for use in a graphics plotter. A movable carriage hangs from a supplemental inverted T-shaped track below the main carriage track of the plotter. The pinch roller is pivotally attached to an arm from the carriage. A leaf spring on the carriage pulls the carriage loosely into positional alignment with the pinch roller aligned with the drum while allowing translational movement easily. A second bias spring urges the pinch roller down and the carriage into gripping engagement with the supplemental track with sufficient force to prevent translational movement thereof. A release bar holds the pinch roller off the drum and releases the gripping force to allow the carriage to be slid for adjustment.