Abstract: An active current steering semi-digital FIR filter for a digital-to-analog conversion circuit, which includes a shift register having a 1-bit digital input stream and a plurality of output taps, where each output tap provides a 1-bit signal which has a value of a logic 1 or a logic 0, and a plurality of current paths, where each path includes an active element, such as a transistor, having a relatively high output impedance, which is connected to a common current source, and to an op amp for current-to-voltage conversion. The relatively high output impedance of the active current steering element causes any error term resulting from offset at the op amp inputs to be minimized.

Abstract: A hand held data entry apparatus having a body for receiving, storing and transmitting information, including a camming mechanism for quickly sealingly attaching an accessory such as a scanner to the top of a hand held data entry apparatus. Additionally, a similar camming mechanism is utilized to hold a battery pack in place with the additional feature of not only pulling the battery pack securely against the housing, but also pushing the battery pack contacts into abutment with complementary contacts disposed within the housing. A keypad is provided for permitting information to be manually entered into the hand held body and this keypad is encased in a layer of elastomeric material such as silicone. A pair of LED's are utilized, one to indicate a "good scan" and the other to indicate something else, such as a "bad scan." Additionally, these LED's can be encased in operative or dummy keys in order to save keyboard space. A mechanism is provided for pivoting the scanner about either of two perpendicular axes.

Abstract: A hand-held data collection terminal unit includes an elongate housing having a lower portion supportable in the hand of a user and an upper portion facing such user when the terminal is in a typical use position. The upper portion includes a keyboard and a display screen. In accordance with the invention, the hand-held terminal comprises a plurality of modules in which a base modules extend longitudinally and includes inner and outer end caps of the terminal. The inner end cap is disposed on the end of the terminal which is typically points toward a user when the terminal is in use, the out end cap being disposed on opposite end of the terminal. A keyboard module is defined as an intermediate module disposed adjacent the base module and between the end caps. A display screen module is further disposed adjacent the intermediate module and adjacent the outer end cap of the base module.

Abstract: A battery capacity monitoring system readily indicates the remaining capacity of an uninserted battery pack upon an operator's request. Such request may involve the touching of one or more contacts disposed on the battery pack. The battery pack also includes a display and a communication means for communicating capacity information to the device in which it may be installed. The communication means may also be used to display status when the battery pack is not inserted. When inserted a device, the battery pack and device participate to determine time estimates for remaining battery life based on known device loading characteristics and current battery capacity. An operator viewing such information may more adequately determine the usage value of the current battery charge. Moreover, the battery pack and corresponding device are configured to detect the beginning of the process of removing a battery pack. In response, the device saves operational states and data before losing power.

Abstract: A substrate support apparatus for supporting one or more substrates in a substrate carrier for achieving a minimum amount of sagging of the substrates. A first support rod is positioned to support one side of each substrate along a first support contact line and a second support rod is positioned to support the other side of the substrate along a second support contact line. The first and second support contact lines are referenced to a centerline of the substrate. In particular, both contact lines are offset by a certain distance on either side of the centerline, where the particular offset of the support lines is determined by finite element analysis of the substrate to achieve as little sag as possible. The rod support member preferably includes two cantilevered beams mounted on either side of each of the support rods. Also, a plurality of support rods and corresponding rod support members are provided for supporting as many substrates as necessary in the carrier.

Abstract: This invention is for a single monolithic audio processing integrated circuit which includes a synthesizer module, a CODEC module and an external serial data port in the CODEC module for bi-directional serial data communication between the CODEC module and an external serial data device, such as a digital signal processor. A serial data path between the synthesizer module and the CODEC module is also included.

Abstract: A computerized system for managing freight or the like which is picked up at various points and delivered to other various destinations, and more particularly to such a system which utilizes hand-held terminals, scanners and printers which are linked together by a micro link radio to each other and by a wide area network radio link to a main area station which can receive and transmit information to a plurality of sets of terminals, printers and the like for managing an overall freight system.

Abstract: A rechargeable battery system utilizes intelligent temperature control to enhance and optimize battery cell capacity and performance in low and high temperature environments. A temperature varying element (heating and/or cooling) modifies the temperature of battery cells utilizing an amount of energy that is less than that gained by making such temperature modification. A control circuit optimally control the temperature varying element to maximize battery operation. The control circuit also utilizes the temperature varying element to prevent cell damage in extreme conditions. A battery pack contains a plurality of cells also houses the control circuit, the temperature varying element and a temperature sensor. At least a portion of the control circuit and temperature varying element may alternately be located within a portable electronic device. A second temperature sensor may be added to monitor ambient temperature, and Insulating material may be used in the construction of the battery pack housing.

Abstract: A portable, hand-held data collection terminal unit is of modular structure including among other modules a display screen module, a keyboard module and a base module, each of which may be chosen from a plurality of modules available for assembly into the terminal unit. Consequently, a wide combination of terminal units may be assembled from a comparatively limited number of modular choices, such that the cost of assembly of a terminal unit with specific functions may be minimized A particular selected module is a scanning module including a pivotable scanning head to permit a user to adjust the scanning head to a convenient position for operating the scanning module without sacrifice of visual access to a display screen of the display screen module. The display screen module may be selected from modules of standard width equal to the width of the terminal unit, of extended width extending when assembled to a selected keyboard module beyond either or both lateral edges of the terminal unit.

Abstract: A hierarchical communication system, arranged in a spanning tree configuration, is described in which wired and wireless communication networks exhibiting substantially different characteristics are employed in an overall scheme to link portable or mobile computing devices. Copies of data, program code and processing resources are migrated from their source toward requesting destinations based on request frequency, communication link costs and available local storage and/or processing resources. Each appropriately configured network device acts as an active participant in network migration. In addition, portable two-dimensional (2-D) code reading terminals are configured to wirelessly communicate compressed 2-D images toward stationary access servers that identify the code image through decoding and through comparison with a database of images that have previously been decoded and stored.

Abstract: A modular, transportable for storing substrates, such as semi-conductor wafers and masks, and for maintaining such substrates in a substantially clean environment. Substrates are supported within the housing by a plurality of combs which maintain the substrates in spaced relationship relative to each other. Access to the interior of the housing is permitted by a pivotal door assembly. A docking unit permits interface of the housing with a clean environment. Control circuitry provided in the docking unit detects the presence of a housing and loads/unloads the housing as directed by a host computer through a communication link. A memory device is preferably mounted to the housing for storing history and other information about the substrates within the housing. The host computer directs the control circuitry to retrieve the substrate information from the memory and relay the information to the host computer. During or after processing of the substrates, the host computer updates the memory as desired.

Abstract: In a preferred data capture system, a RF data terminal is capable of use alone or with any of a series of scanner modules incorporating diverse scanner technologies such as CCD bar code scanning, area image data reading, cyclically swept laser beam bar code scanning, and RF identification label scanning. In each case, a frontal operating panel of the RF terminal--scanner system is held facing the user during scanning, whether the system is held with the right or left hand. Scanner data is supplied to the-RF unit by mating connectors or the like. From the RF unit, the scanner data may be transmitted on-line to a host computer or other receiving station. The family of scanner modules may provide respective laser scanners with respective different wavelengths of illumination so that an optimum module may be selected for reading respective bar codes of differing color characteristics. The family is readily upgraded to incorporate new light sources of greater efficiency and/or more advantageous spectrum.

Abstract: A three-way power switch for turning on and off an entire computer system with a single switch. The host computer includes a soft-start circuitry for detecting display data channel (DDC) activation signals from a DDC-capable monitor. Thus, a toggle power switch on the monitor turns on and off the entire system, where the computer powers up or down based on the presence or absence, respectively, of the DDC signals. In a second embodiment, the monitor includes soft-start circuitry which detects the presence/absence of video signals from the host computer for powering up/down the monitor, respectively. Thus, in the second embodiment, a power switch either on the monitor or computer system is used to turn on and off the entire system. A third embodiment is similar to the second embodiment except bi-directional DDC2 signals are used as an activation signal to power up or down the monitor.

Abstract: The present invention is for an implementation of a multi-stage digital decimation filter and a method of decimating a multi-bit input signal, where n/2 additions are performed, where n=the number of bits in each filter coefficient. A compensation stage is also provided. Scaling and multiplication of data with coefficients is performed using a common architecture to the Decim. 2 and Decim. 3 stages. Coefficient values, having an associated scaling factor, are stored in memory. The coefficients are stored in coded form, and are then decoded prior to multiplication by the data values.

Abstract: A communication module for use with a portable terminal. The module includes a housing, mounting apparatus, a radio frequency transceiver and an indicia reader connector. The module can enable real-time, on-line communication with a remote host. The system can also include an antenna.

Abstract: A network is disclosed which utilizes modified preambles in a communication network to facility antenna diversity and multipath compensation. In one embodiment, an antenna diversity protocol first directs a mobile transceiver to select any antenna that enables successful receipt and identification of at least a portion of the preamble, i.e., the selection of a satisfactory antenna. Once a satisfactory antenna is identified, the diversity protocol extracts from received portions of the preamble information necessary to determine whether there is enough preamble remaining to conduct a best antenna search. If so, the other antennas are sequentially selected to evaluate their performance. Thereafter, the diversity protocol directs the mobile transceiver to select the best antenna based on a performance comparison.

Abstract: An apparatus and a method for routing data in a radio data communication system having one or more host computers, one or more intermediate base stations, and one or more RF terminals organizes the intermediate base stations into an optimal spanning-tree network to control the routing of data to and from the RF terminals and the host computer efficiently and dynamically. Communication between the host computer and the RF terminals is achieved by using the network of intermediate base stations to transmit the data.

Abstract: A high swing, low power output stage for an operational amplifier is provided which includes: 1) a folded-cascode gain stage having a differential pair of natural V.sub.T devices, which are preferably P-channel transistors; 2) a source-follower input stage connected to the folded-cascode gain stage and to the input of the high swing output stage; and 3) a source-follower output stage connected to the folded-cascode gain stage connected to an output of the source-follower stage and to the output of the high swing output stage. The high swing output stage also includes a compensation capacitor which is used to provide dominant pole frequency compensation for the high swing output stage.

Abstract: A battery backup system using a power factor correction (PFC) front end as a DC-to-DC converter of a power supply for supplying a regulated DC input signal to a main power converter. The battery backup system includes a battery backup for supplying power, a switch circuit for connecting the battery in the event of loss of the AC input signal and a detection circuit for detecting the presence or absence of AC power for controlling the switch circuit. The PFC front end preferably receives either a pulsing DC voltage from a bridge rectifier or the battery voltage and switches this voltage through a series inductor for providing the regulated DC input voltage to the main power converter. The battery is switched in to replace the AC source and rectifier in the event of loss of the AC signal. In the preferred embodiment, the PFC circuit includes a series inductor and diode, a switching transistor and a control circuit for providing the regulated DC input voltage.

Abstract: The present invention is for an implementation of a multi-stage digital interpolator and a method of interpolation, where n/2 additions are performed, where n=the number of bits in each filter coefficient being multiplied. Scaling and multiplication of data with coefficients is performed using a common architecture. Coefficient values, having an associated scaling factor, are stored in memory. The coefficients are stored in coded form, and are then decoded prior to multiplication by the data values.