Abstract: A joystick for moving a cursor on a display screen uses an infrared transmitter (34) radiating into a transparent handle (14). As the handle is moved by an operator, infra-red light is directed to one of four optical detectors (31) covering up, down, left and right directions respectively. The device can also detect movement at 45 degrees to any of these directions since light is then directed to two detectors (31). A further four optical detectors (31a) are provided, each arranged adjacent one of the first four detectors (31), so that further movement of the handle in the same direction can be detected. An additional optical detector (37) is arranged to detect downward movement of the handle (14) against a spring (24). The handle is translatably mounted, rather than pivotally mounted as in a stand joystick.

Abstract: The latch (100) includes a catch (102) having a beveled edge (102A). An aperture (104) receives a downward force to release the catch from the lip (106A) of a housing (106). A stop (108) limits the downward movement of the latch. A retaining tab (110) traps the latch within the door pocket and limits the upward movement of the latch. The retaining tab includes a beveled surface (110A) to facilitate the insertion of the latch into the pocket. A cantilever spring (112) exerts an upward force on the latch when compressed. The latch, including all of its associated parts, can be plastic injection molded in a single-action mold. The door (200) includes a substantially parallelepiped pocket (202) having an opening at the top to receive the latch. The pocket includes a front aperture (202FA) in the upper, front surface (202F) of the pocket, and a rear aperture (202RA) in the lower, opposing rear surface (202R).

Abstract: The computer is adapted to be used and stored on its narrow bottom surface (24), which has an area which is less than the area of the front surface (25) of the computer. A keyboard (4) is pivotally mounted to the back of a cover on the front surface. A floppy disk drive (3) is pivotally mounted behind the cover and the drive can be operated in the open or closed positions. A movable flat display (2) is positioned parallel to the front surface of the computer when the display is in the retracted position. A frictional mechanism (FIG. 5A) permits the display to be positioned at any angle.

Abstract: A class of adaptive hybrid multiple access protocols for a single channel, time division communications network dynamically switches among contention (Aloha), reservation, and fixed assignment (TDMA) protocols as a function of the traffic on the channel. This class of protocols is referred to as "Aloha-Reservation-TDMA" or "ART" class protocols. Within the ART class, a subclass of protocols is defined for satellite communication networks. This subclass is referred to as "Adaptive Satellite Hybrid Access" or "ASHA," and two examples of protocols within the ASHA subclass are described to show the viability of the ART class protocols. These protocols are referred to as ASHA1 and ASHA2. Both the ASHA1 and ASHA2 protocols combine the features of S-ALOHA, TDMA-Reservation and TDMA protocols. The ASHA1 protocol transmits reservation information when the Aloha protocol is selected, but the ASHA2 protocol does not.

Abstract: Each section (e.g., 102) of the ring oscillator consists of three two-input NOR gates; one in the feedforward path (108), one in the feedback path (112), and one in the crossover path (110). The center frequency of the oscillator is controlled by enabling and disabling the appropriate gates, such that a single closed loop path is formed. The gates in the feedforward and crossover paths are directly enabled or disabled (to disable, either input is held high) from a control circuit (FIG. 2). The gates in the feedback path, however, are indirectly enabled and disabled. To enable a particular feedback path gate (e.g., 118), either the corresponding crossover gate (116) is disabled, or the corresponding feedforward gate is disabled (114) and the crossover gate (122) in the following section is enabled. The later causes the feedback gate (124) in the following section to be disabled, thereby removing the remaining sections (106) of the oscillator from the closed loop path.

Abstract: The preferred housing includes an integrally molded thermoplastic base (102) and cover (104) assembly. The cover is joined to the base by a living hinge (106) and a peripheral wall (108) extends around the perimeter of the base. In one embodiment, the antenna is a wire loop (204), the wire being wound in an external circumferential groove (202A) in the peripheral wall or, alternatively, integrally molded into the peripheral wall. Other embodiments use printed circuit loop antenna patterns that are preferably vacuum deposited directly onto the thermoplastic base and/or cover. When the antenna pattern is disposed on both the cover and the base, a portion of the antenna (e.g., 1002K) is also disposed on the hinge to join the main portions of the antenna on the base and cover. In one embodiment of the printed circuit loop antenna, the plane of the loop lies parallel to the base and may include one or more turns or loops (e.g., 402C, E, G and J). In another embodiment, the loop includes a 90 degree bend (e.g.

Abstract: A retaining washer (100) prevents the rotation of a D-shaped shaft (106) which is mounted in a round hole (105a) of a housing (105). The retaining washer includes a substantially flat washer (101) having a hole (101a). A tapered tab (102) includes a wide end (102a) and a narrow end (102b). The tab is attached to the flat washer at the wide end such that the tab is substantially perpendicular to the flat washer. A gusset (103) is attached between the tab and the flat washer. The gusset includes a lower edge (103a) which is positioned at an obtuse angle (104) relative to the flat washer. The gusset indents into the housing (105b) and the tab is forced against the flat portion (106b) of the D-shaped shaft. The upper left and right edges of the tab cut into the wall of the housing hole (105c and 105d).

Abstract: The alert circuit includes a minimum number of inexpensive descrete electronic components to provide a flashing alert when battery voltage drops below a predetermined trigger voltage. A single unijunction transistor circuit functions as a combination low voltage detector and oscillator to output periodic pulses to an LED annunciator circuit when battery voltage is low.

Abstract: This process uses a metal lift-off step and results in a layer of polyimide covering the surface of an integrated circuit, except at the bonding pads which are covered by metals. A layer of polyimide is applied to the surface of an integrated circuit and then partially cured. A layer of positive photo-resist is applied over the polyimide layer and then pattern exposed and developed, resulting in windows being opened up over the bonding pads of the integrated circuit. The remaining photo-resist is then flood exposed. One or more metals are then sputtered over the resist and the bonding pads. The integrated circuit is then immersed in solvent and the remaining layer of photo-resist, including the metal above it, is lifted-off. Only the metal over the bonding pads remains. The polyimide layer is then fully cured.

Abstract: A radio includes a frequency synthesizer that is under the control of a microcomputer. Stored in the microcomputer's memory is a menu of predetermined frequencies from which a particular frequency is selected by scrolling through the menu. Activating a first switch causes the microcomputer to scroll in one direction while activating a second switch causes the microcomputer to scroll in the opposite direction. A display, positioned on the top of the radio, displays a character set indicative of the particular frequency selected. When both switches are activated simultaneously, the orientation of the character set appearing in the display is inverted, and the scrolling direction of each switch reverses.

Abstract: An antenna switch (302) includes a radio terminal (R) and first and second antenna terminals (A1 and A2). When the second antenna terminal (A2) is unterminated, the radio terminal (R) is coupled to the first antenna terminal (A1). When the second antenna terminal (A2) is connected to a remote antenna system (304), the switch automatically couples the radio terminal (R) to the second antenna terminal (A2). Thus, the switch does not require a separate control terminal (C) and control signal to switch between the first and second antenna terminals. Instead, the switch is controlled by the presence or absence of a DC current at the second antenna terminal (A2). The remote antenna system includes a remote antenna (308) and a low pass filter (310) coupled between the remote antenna and ground. An alternate embodiment is described which includes a DC amplifier (402).

Abstract: An antenna is provided which includes a half wave helical element RF coupled to a monopole element. The monopole element is situated on the axis of the helical element and extends into the helical element a distance sufficient to permit resonant coupling between the helical element and the monopole element. The monopole element is driven by a source of radio frequency energy such that the helical element coupled thereto is excited by such radio frequency energy.

Abstract: A laminar antenna includes a conductive ground plane (102), a first dielectric lamina (106), a conductive exciter lamina (108), a second dielectric lamina (114), and a conductive radiator lamina (116). The radiator partially overlaps the exciter and the amount of overlap determines the input impedance of the antenna. The laminar antenna can be positioned within the wall of a plastic radio housing (302). Multi-radiator wideband and duplex embodiments of the antenna are also described. In another embodiment, the ground plane extends above the radio housing while the radiator and dielectric laminae wrap around the extended portion of the ground plane.

Abstract: A stripline filter resonator structure is provided which exhibits high Q and results in a filter with low insertion loss. The dielectric consists of two sections of dielectric material. A groove shaped as half an ellipse is formed in each of the sections. The surface of the grooves are covered with electrically conductive material. The two grooves are aligned and filled with adhesive material to hold the two dielectric sections together. An elliptically shaped resonator is thus formed in the center of the dielectric sandwich. Ground plane layers are respectively situated on the outer layers of the dielectric sandwich thus forming a stripline resonator structure. This unique resonator structure results in a more uniform current density around the periphery and thus undesired current bunching is correspondingly decreased.