Abstract: Modular, portable data collection terminals are disclosed for use in mixed wireless and hard-wired RF communication networks, wherein various radio transmitter modules and associated antennas may be selectively added to a base terminal unit to solve networking problems associated with specific types of business environments. Modularity exists in both the hardware (splitting data collection and processing control circuitry from radio transceiver control circuitry) and software (splitting transceiver-specific, lower level communication protocol from generic, higher level communication protocol). The control circuitry, including associated microprocessors devices, interact to selectively activate communication circuits to perform necessary communication or data processing functions and enter and remain in a power-saving dormant state during other times. To support such dormant or "sleeping" states, a series of communication protocols provide for channel access to the communication network.

Abstract: A feedback sensing system including a control circuit for detecting power failure of either power supply, and for controlling first and second switch circuits to modify the feedback sensing path of the other supply to the output load. In this manner, when one power supply fails, the feedback sensing path of the other power supply is rerouted to the output node to directly monitor and regulate the voltage across the load. Each switch circuit preferably operates to switch between two nodes along the respective output paths of the power supply, including a first node located before the current control device and a second node located between the current control device and the load. In one embodiment, each switch circuit includes two switches operated in a mutually-exclusive manner.

Abstract: A redundant network and communication protocol is disclosed having host computers, RF base stations and roaming terminals. In one embodiment, this network utilizes a polling communication protocol which, under heavy loaded conditions, requires that a roaming terminal wishing to initiate communication must first determine that the channel is truly clear by listing for an entire interpoll gap time. Thus, when a "hidden" terminal is communicating, the roaming terminal can conclude that such communication is taking place upon receiving a polling frame directed to that "hidden" terminal from the normally silent base station. In a further embodiment, a criterion used by the roaming terminals for attaching to a given base station reduces conflicts in the overlapping RF regions of adjacent base stations.

Abstract: A power switch detection system for a power supply including an operator-accessible power switch coupled to the secondary ground of the power supply and to one side of an isolation capacitor. The other side of the isolation capacitor is coupled to a switch detection circuit referenced to primary ground for detecting the state of the power switch through the isolation capacitor. The switch detection circuit controls a control circuit on the primary side based on the state of the power switch, where the control circuit correspondingly controls the power state of the power supply and a corresponding electronic device. In this manner, the power switch remains isolated by the isolation capacitor but controls the power state of the device. The control circuit controls conversion of AC power from an AC source coupled to the primary side through a transformer.

Abstract: A power loss detection system for a power supply including a main converter for providing regulated power, an activation circuit for mining on and off the main converter based on an active low activation signal, a standby power circuit for providing a standby power signal, and an internal pullup resistor coupled between the standby power and activation signals. The power supply asserts a power status signal indicative of the status of regulated power. Alternatively, an external detection circuit monitors the regulated power from the power supply and asserts a power loss signal indicative thereof. The control circuit asserts the activation signal low to turn on the main converter or floats the activation signal to turn off the main converter. If the power good or power loss signal indicates loss of regulated power, the control circuit floats the activation signal. If the activation signal goes or remains low after the activation signal is floated, then the power source has failed.

Abstract: A stage assembly for a substrate processing system including a cassette support assembly for receiving and supporting a cassette and an actuation and support assembly for supporting and moving the cassette and cassette support assembly between a loading position and a processing position. The processing position provides convenient and efficient access by a central processing system, and the loading position preferably places each cassette closer to, and aligned with, a front panel of the processing system for convenient access by an operator. The actuator and support assembly preferably includes a frame assembly and a rotating plate pivotally mounted to the frame assembly, where the cassette support assembly is mounted to the rotating plate for pivoting relative to the frame assembly. An actuator assembly mounted to the frame assembly flits the cassette support assembly between the loading and processing positions. A shaft assembly pivotally mounts the cassette support assembly to the rotating plate.

Abstract: A processor having two separate and relatively independent memory controllers to achieve a dual interface architecture. A first memory controller is coupled to the host interface for retrieving data and instructions and a second memory controller is coupled to an independent local bus for interfacing with a frame buffer memory. A depth buffer may also be coupled to the local bus if desired. Address multiplexor logic is preferably included to allow either memory controller to address either external bus. Multiplexor and buffer logic is also preferably included to allow data transfer in either direction. Preferably, the processor is a graphics processor and both memory controllers are programmable for different addressing formats, such as linear and X/Y in the preferred embodiment. In this manner, data is transferred from host to local memories, and vice versa, in any desired format without delays due to memory controller reconfiguration.

Abstract: A universal offline switch mode power supply including an input stage having an input filter inductor and a switch for switching between a first lower AC input voltage or a second higher AC input voltage. A bridge rectifier full-wave rectifies the higher AC voltage when the switch is in a first position, where the filter inductor serves to filter the higher AC voltage. The higher AC voltage is preferably approximately 230 V rms. The bridge rectifier and two bulk capacitors serve to double the lower AC voltage when the switch is in a second position, where the lower AC voltage is preferably approximately 115 V rms. Also, the input filter is bypassed for the lower AC voltage. The switch is preferably an SPST switch. In the preferred embodiment, the inductor is placed between one AC input line and one input of a bridge rectifier circuit. The outputs of the bridge rectifier circuit are placed across two series input bulk capacitors and to the input of a switchmode power converter.

Abstract: A hierarchical communication system is described in which wireless local area networks (LANs) exhibiting substantially different characteristics are employed in an overall scheme to link portable or mobile computing devices. In a premises LAN, a series of radio base stations and a backbone LAN make up an infrastructure network. The infrastructure network and at least one mobile computing device make up a higher-power LAN, utilizing a frequency hopping protocol. A lower-power LAN allows for radio communication between a mobile computing device and peripheral devices, utilizing a single-frequency spread spectrum protocol. A vehicular LAN provides for short-range communication between a vehicle terminal and a portable terminal. When out of direct RF range of the premises LAN, the vehicle terminal maintains indirect communication when necessary with the premises LAN via one of several alternate RF channels.

Abstract: A power supply system including a power supply providing power to an electronic device through current share circuitry, which includes a second connector for receiving power from an external power supply. The power supply is preferably a fault-tolerant power supply so that the electronic device receives continuous power in the event of partial failure. When the fault-tolerant power supply partially fails, the external power supply is connected to the second connector of the current share circuitry, which is switched to temporarily provide power to the electronic device from the external power supply. The power supply is then replaced while the external power supply provides power, so that power to the electronic device is continuously maintained. The electronic device thus experiences zero down-time. Even in low-end systems with a single power supply, down-time is substantially reduced. The external power supply is connected internally or through an external connector on the electronic device.

Abstract: An isolated low power converter including a low voltage, self-oscillating power converter, which derives power through bleeder current from the relatively high-voltage, input bulk capacitors. A bleeder circuit taps a relatively low voltage current source from the bulk capacitors to supply an oscillator circuit. The bleeder circuit preferably incorporates current limit resistors typically provided according to safety specifications. The oscillator circuit is preferably implemented using the primary of a transformer. A simple regulator circuit coupled to the secondary of the transformer provides a low voltage SELV power signal for powering detection circuitry. In the preferred embodiment, the bleeder circuit includes a relatively large resistive voltage divider for supplying current to charge a capacitor. The voltage of the capacitor is regulated using a constant voltage device, such as one or more Zener diodes.

Abstract: An incremental orthogonal error correction process for 3D graphics for correcting errors or otherwise reducing abrupt changes in the characteristics of adjacent pixels while interpolating a polygon into a pixel grid. Error values are calculated for each desired characteristic to be corrected, where the error values are calculated based on the slope of the main slope and the orthogonal slope of the corresponding characteristic value. Thus, the error values adjust the characteristics of the pixels in the scan line to adjust for the slant of the main slope of the polygon. An interpolator for each corrected characteristic accumulates the error value in the opposite direction as the corresponding orthogonal slope. When the fractional component of the x parameter overflows, the orthogonal slope values are subtracted from the corresponding accumulated error values to thereby reduce the magnitude of the error values.

Abstract: A fan test system and method for determining fan bearing friction and available life, including a power controller for changing the fan's power level for at least a predetermined time period and a measuring device for measuring the change in rotation of the fan. A memory is preferably coupled to the power controller for storing a plurality of rotation values for providing a history of fan bearing performance. A current sensor or current limiter is preferably coupled in series with the fan, where the measuring device detects voltage pulses or poles of the fan. The power controller preferably includes a timer for determining the time period and a counter for counting rotation events. The power controller also preferably includes a control circuit for controlling a switch coupled between a power source and the fan.

Abstract: A fault tolerant isolation system providing fault tolerant electrical isolation between different components receiving power from separate power sources regardless of which of the power sources fails. One power source provides operating voltage to an isolation device, which is a transceiver, buffer, quick switch, etc. The other power source activates a transistor switch coupled to the output enable input of the isolation device, and a current limit device is provided between the output enable and power inputs of the isolation device. In this manner, failure of either power source disables the isolation device and therefore provides fault tolerant isolation between the devices on either side. In the preferred embodiment, the isolation device acts as a high impedance open switch if its power is removed thereby isolating the devices on either side.

Abstract: A fail-safe system for monitoring the voltage of a backup battery of a portable computer system to prevent excessive drainage of the backup battery. The backup battery is primarily provided to maintain voltage to the configuration memory of the portable computer during swapping of the main battery. A timing circuit allows the backup battery to provide power to other, low power system components for a limited time, such as two minutes, while the main battery is being replaced. In the fail-safe circuit, a comparator circuit monitors the voltage of the backup battery and asserts a signal in the event its voltage falls to a predetermined minimum level. A switch circuit correspondingly disconnects the backup battery from the other system components, thereby conserving the energy of the backup battery.

Abstract: A leadless high density connector including a plurality of connector pins each having multiconductor pins electrically connected to solder balls on the back side of the connector for interconnection to a PWB. The solder balls form a ball grid array (BGA), which replaces thin gull wing leads used on connectors of prior art. The use of BGA technology as applied to high density connectors provides a plurality of benefits associated with BGA technology. The signal carrying capacity of the connector is increased since the bottom surface of the connector is available for interconnecting signal paths rather than being limited to the peripheral edges as common for leaded packages. The resulting profile of the connector is substantially reduced allowing increased component and wiring density. The resulting bond strength using BGA technology is greater than that with a leaded equivalent due to the increased bond surface area and resulting anchoring effect.

Abstract: A computer device for receiving and utilizing a radio card. The radio transceiver is self contained inside the radio card and has antenna contacts disposed on the radio card on one end and an electrical interface on the other. The computer device receives the radio card such that it engages the electrical interface. The computer device additionally has and cap which covers the opening into which the radio has been inserted. Antenna contacts are disposed on the cap to engage the antenna contacts on the radio card. At least one antenna is operably connected to the radio card through the cap. A band is used to attach the cap to the housing of the computer device. The antenna or antennas are embedded in the cap, in the band, or embedded in or attached to the housing of the computer device. Positioning two similar antennas in different position creates an antenna diversity scheme. Shielding can be added to the cap to help reduce the escape of electronic noise.

Abstract: DC level control for an electronic telephone line card which filters the DC component from the input audio signal, determines the gain setting of the transmit path, develops a DC adjust voltage opposite to that of the DC shift component and subtracts the DC adjust voltage to the input voltage to cancel the DC shift component. A quantized, discontinuous feedback path is implemented to respond only to DC shifts so the AC operation remains substantially unaffected. Such discontinuous feedback eliminates stability and impedance matching problems introduced with continuous feedback solutions. A DC control circuit according to the present invention includes a low pass filter for detecting DC shifts, a quantizer for asserting an incremental signal, a threshold detector for activating adjustment functions, and an accumulator for developing the DC adjust voltage by incremental steps.

Abstract: A presumptive mode computer aided design and drafting system for interactively manipulating and displaying graphic objects that employ predefined rules to govern the geometric layout and logical relationships representing a physical design, schematic or process flow diagram. The system is configured to comply with the rules employed by various design disciplines. Specific interactive computer graphics behavior is dynamically accessed to interactively update graphic object relationships according to rules of geometric conduct. The rules of geometric conduct may be stored in external databases along with parameters to verify the logical relationships of the graphic objects used in the drawing. Object orientation is employed in the software design of the system to allow new devices or procedures to adopt the behavior of existing definitions. In the preferred embodiment, a selected object floats with a cursor in a graphic environment until located in proximity with underlying graphic objects.

Abstract: A method for catalyzing a gas diffusion electrode (GDE) with a catalytic material mixed with a solubilized electrolyte, where the electrolyte preferably comprises a perfluorocarbon sulfonic acid copolymer. The catalytic material and solubilized electrolyte are mixed to form a paste or the slurry, which is then applied layer by layer onto the catalyzable side of the GDE while the electrode is kept on a hot plate at a temperature of approximately 80.degree.-100.degree. C. The electrode and the catalyst layers are then dried in an oven at a temperature of about 100.degree. C. for about 10 minutes. The catalytic material preferably comprises a metal, such as platinum, and is further mixed with a supporting material comprising a high surface area carbon, resulting in a platinum-on-carbon mixture.