Abstract: A phase-angle circuit (24) processes the outputs of an antenna array (12) to apply to a compressive receiver (20) an ensemble of signals having components whose spatial frequencies are proportional to the bearing angle of the electromagnetic plane waves that give rise to them. A signal whose phase angle is equal to twice the bearing angle is generated by interconnecting the antenna elements as two quadrupoles offset by 45.degree.. The output of one of the quadrupoles is shifted in phase by 90.degree. and added to the output of the other quadrupole to generate the desired signal, which is applied as an input to the compressive receiver. Other inputs to the compressive receiver are generated in similar ways. The position of the compressive-receiver output port (22) at which a maximum occurs indicates the bearing angle of the electromagnetic plane wave that gave rise to the maximum.

Abstract: Universal logic circuit cells for use in designing and laying out electronic circuits. The cells provide AND and OR on other logical functions on input signals, and include a conventional AND or OR gate, or other logic gate, and associated input and output connections and circuitry that enables them to be used in many applications. The cells simplify laying out a combinatorial logic circuit after it has been designed.

Abstract: A circular frequency-independent antenna array (10) includes a plurality of radially extending log-periodic subarrays (12, 14, 16, 18, 20, and 22) of slot radiators (26) provided in a ground-plane conductor (28). Associated with each slot is a cavity (34) into which the slot opens. A traveling-wave element in the form of a wire (30) cooperates with a ground-plane conductor (28) in which the slots are provided to support propagation of an electromagnetic signal. The signal is radiated upon encountering a slot that resonates at a frequency near that of the signal, and the depths of the cavities are adjusted so that the phase relationships between the radiation from the slots and the signal propagated along the traveling-wave element results in an antenna pattern that launches radiation in a direction away from the center of the array. Direction-finding errors are reduced because interference between the several subarrays is kept to a minimum.

Abstract: A thermal printer of the three-pass variety for printing in color featuring a sheet feeder, automatic registration, and ejection of the sheet when printing is complete. A rotatable, cylindrical drum has the print head close adjacent thereto and includes a releasable clamp for receiving the paper from the sheet feeder. The paper is clamped to the drum and the drum rotated past the print head three times, one for each color. The drum is then rotated to release and eject the paper. Sensors are provided to detect and monitor the position of the drum during its printing operation and to monitor the status of the paper supplied to the clamping mechanism.

Abstract: A graphics drum plotter in which wide strip paper is divided into virtual columns. An operator interface is provided whereby an operator can define the size and number of columns across the strip paper. Instead of producing a series of small plots along one edge of the wide strip, the system includes logic to place the series of plots sequentially across the columns of the strip paper before advancing the strip paper to a next writing area. A paper slitter is also provided to slit the paper on the column lines after the printing thereon.

Abstract: An X, Y plotter particularly adapted to use both cut paper and strip paper. A driven roller provides motion of the paper back and forth according to one signal. A moveable pen block containing the pen is moved transverse the path of the paper in response to the second signal, thus providing controlled motion in the X and Y directions. According to one aspect, an idler roller is provided parallel to the driven roller around which an endless belt is disposed to be driven in combination with the drive roller by two pairs of rows of sprockets on the driven roller adapted to mate with holes provided therefor in the belt. Cut paper temporarily attached to the belt with drafting tape or the like is moved beneath the pen for plotting purposes. The inner row of sprockets is adapted for engaging holes in strip paper for moving it beneath the pen.

Abstract: A microwave antenna (10) is excited by two independently driven feed lines (30 and 32) so that the plane of polarization of the resultant microwave radiation depends on the relative amplitudes of the signals on the two feed lines. The feed lines are disposed between two parallel ground planes (12 and 14), in one of which is etched an aperture (18). The periphery of the aperture forms ridges (20, 22, 24, and 26) in registration with the feed lines (30 and 32). Conductive eyelets (27) extend between the ground-plane conductors (12 and 14) to act as shorting elements that surround the aperture to form a cavity defined by the shorting elements and the ground-plane conductors. The resultant antenna, which may, for instance, have a thickness of only one-tenth of a wavelength, achieves a 2:1 VSWR bandwidth on the order of 30%.

Abstract: A low-loss, low-cost passive pulse width to voltage converter is provided by utilizing a diode clamp having a resistor in series therewith to provide a soft clamp or integrating clamp.

Abstract: The housing (12) of a printer-plotter (10) includes a top cover (14) and a front cover (30) on adjoining housing walls. The top cover (14) is biased toward its open position by a gas spring (20) that is held closed by cooperating latch mechanisms on the top cover (14) and the front cover (30) in such a manner that the top cover (14) opens automatically when the front cover (30) is opened. When the top cover (14) is initially closed, a pivotable latch (22) on the top cover (14) engages a catch (24) on the housing (12) to hold the top cover (14) closed. When the front cover (30) is subsequently closed, a disengaging plate (48) causes the latch (22) to pivot out of engagement with the catch (24) and thus permit the top cover (14) to pivot slightly. However, a stop member (54) on the disengaging plate (48) prevents the top cover (14) from opening. Since the latch (22) no longer engages the catch (24), the top cover (14) automatically opens under the force of the gas spring (20) when the front cover (30) opens.

Abstract: Apparatus for sorting two input numbers including a memory that iteratively receives a digit from both of the numbers and transmits output signals corresponding to the input digits, the digits of the larger number being transmitted on one output line and the digits of the smaller number being transmitted onto another output line. The apparatus includes a memory that receives, as address signals, the state signal and signals corresponding to the input digits. The state signal determines the output lines onto which the next pair of input digits are to be transmitted.

Abstract: A new method and apparatus for generating an analog output signal as a function of a digital input in the form of digital words over a specified range. The range is divided into a plurality of intervals, and the function is approximated by a linear segment in each interval. Each linear segment is defined by a step value, which is the value of the linear segment at the beginning the interval, and a slope value, which is the slope of the linear segment in the interval. The function is then approximated for any desired digital word in the range by determining the step and slope values for the interval into which the digital input signal falls, determining an incremental value by multiplying the slope value by the difference between the digital input signal and the value of the digital input signal at the beginning of the interval, and adding the incremental value to the step value.

Abstract: A video disc program branching system comprising multiple programs frequency multiplexed on a video disc and co-located substantially in the same portion of the disc wherein branching is achieved by designating specific ones of said multiple programs through frequency band selection.

Abstract: Guidance is provided for a spinning projectile by measuring the magnitude of the angle between the spinning projectile and a target. This information is processed in conjunction with a body rate sensor to deduce the angular rate of the line of sight between projectile and the target. A means is provided for reducing the line of sight angular rate to zero, thus ensuring that the projectile will intercept the target.

Abstract: A video recorder and playback system adapted to provide the viewer with selectable views of the action in progress. During recording, a plurality of cameras simultaneously record the action in progress on addressable subtracks of a multi-track loop recording medium such as a laser disk or magnetic surfaced disk. At playback time, the playback and display portion of the system is adapted to read from the same subtract on sequential tracks beginning at a selected starting point. Means are provided for the viewer to change on demand the one of the subtracks being read whereby the view can be instantaneously changed by selecting the one of the subtracks containing the desired view.

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.

Abstract: An infrared target seeker for a spinning projectile which does not require any reticle motor or gimbals is provided by a solid unit including lenses, detectors and a reticle, which is etched on one of the lenses.

Abstract: The method of repeatably making an antenna coupler for holding a test antenna in a repeatable fixed position on the exterior surface of an aircraft or the like relative to a working antenna disposed within the aircraft. A positive mold is made of the area adjacent the antenna within the aircraft. A temporary RF shielding box is placed over the positive mold and the mold is modified to support the box repeatably in a fixed position. Pins are provided to interact with mounting holes for an antenna. A permanent box to be used as part of the coupler is mounted on the positive mold. A ribbon gasket comprising a plurality of tubular, compressible members of an RF shielding material and having mounting tabs along the length thereof is disposed against the surface of the mold about the peripheral edge. The gasket and the box are interconnected by an epoxy material, including RF shielding means. The coupler is removed from the mold and the antenna is mounted to the mounting holes.

Abstract: A waveguide-to-stripline transition includes a stripline portion (14) that fits over an opening in one end of waveguide (12). The stripline portion has a cavity defined by an upper ground-plane conductor (20), a lower ground-plane conductor (22), and a rectangular arrangement of plated-through holes (28) that electrically connect the upper ground-plane conductor (20) to the lower ground-plane conductor (22). The upper ground-plane conductor (20) is etched to provide an aperture (32) with a conductive crosspiece (34) extending longitudinally across it. A plated-through hole (36) connects the crosspiece (34) to the center conductor (26) to provide a T-shaped feed element in the cavity. As compared with prior-art waveguide-to-stripline transitions, this transition is mechanically stronger and has higher power-handling capability.

Abstract: A universal logic circuit that performs a selected one of several logic operations on a pair of input signals in response to the receipt of a control signal and the terminals to which the input signals and control signal are coupled.

Abstract: A DC motor particularly adapted to operate in the presence of translational movement between the armature (rotor) and the field (stator) magnets. The field magnets comprise a plurality of magnets formed into a pair of concentric, closed-spaced, parallel rings mounted to rings of soft, magnetic material. The armature is a planar armature wound in a serpentine pattern so as to cross back and form between the rings only on radial lines from a center point on the armature. The radial conductor lines are sized with respect to the width of the magnetic ring such that even in the presence of translational motion, only the radial conductors cross between the rings and the motor can continue to operate.