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 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: A data communication network for providing dynamic routing through both wireless and wired subnetworks to support wireless communication devices and wired remote stations is disclosed. In the wireless network, the wireless communication devices can be mobile RF terminals, while the wired remote stations might be personal computers attached to a wired subnet, such as an ethernet coaxial cable. The wireless network architecture utilizes a spanning tree configuration which provides for transparent bridging between wired subnets and the wireless subnets. The spanning tree configuration provides dynamic routing to and from wireless communication devices and remote stations attached to standard IEEE 802 LANs.

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 termination scheme for twisted-wire pairs for network communication systems, such as Fast Ethernet 100BaseTX, where the wires are electrically connected together and a single resistor is coupled in series between the junction of the wires and ground. A capacitor may also be coupled between the resistor and ground for DC isolation purposes. The single resistor preferably has a resistance equivalent to half of the common mode impedance between the unused pairs. The two wires of each pair are shorted together since there is no differential signal between the two wires. In this manner, two differential impedance resistors are eliminated, thereby reducing size and cost of the system without degrading performance.

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: 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 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: A communication system for allowing a master to send commands to one or more slave devices across a normally static digital signal line of a bus. The master includes command logic for asserting a sequence of digital pulses according to a predetermined protocol with inherent timing to clock each data bit into a slave device. The master transmits several data bits to form each command, where each data bit is combined with clocking pulses to implement the self-clocking scheme. In particular, an initial data pulse incorporates a data bit to initiate a data phase. Each slave device includes a state machine which detects the data pulse and enables a sample and hold or latch circuit to capture the data bit. Then a clock pulse followed by a reset pulse is sent to clock the data into the slave device and reset the state machine. The slave also includes shift register logic to hold a command bit and address bits for each command.

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.

Abstract: A fan speed monitoring system for interfacing a fan, including a fan drive and sensing circuit for maintaining the voltage of the fan's TFSC pin above a minimum voltage level, thus maintaining continuous power to the fan. The fan drive and sensing circuit includes a control loop having an isolation resistor for enabling superposition of fan pulses asserted by the fan on the TFSC pin. The fan speed monitoring system also includes a filter circuit for filtering and amplifying the fan pulses and providing corresponding filtered pulse signals. The fan drive and sensing circuit includes an active control loop for maintaining the voltage of the TFSC pin at an average level above the minimum voltage level, while also enabling inclusion of the fan pulses. The filter circuit preferably includes an AC amplifier for amplifying the fan pulses and a level transition comparator for converting the amplified fan pulses to the filtered pulse signals having the desired form.

Abstract: A configuration system including a processor having memory for storing operating parameters and configuration logic for retrieving the operating parameters and configuring a computer system to achieve a desired performance level. The configuration logic preferably includes programmable regulators, such as a voltage regulator and a clock synthesizer, for asserting an operating voltage and clock signal, respectively, to the processor. These operating signals are asserted at nominal levels at start up to allow the processor to operate at a reduced, yet adequate performance level. The stored operating parameters are asserted onto a processor data bus by the processor during start up and stored in corresponding data latches. The parameters are further provided to the programmable regulators, such as a voltage regulator, a clock synthesizer, for example, which convert the operating signals from the nominal levels to optimal levels corresponding to the retrieved parameters.

Abstract: A packet-based, 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. The network accommodates real time voice transmission both through dedicated, scheduled bandwidth and through a packet-based routing within the confines and constraints of a data network. Conversion and call processing circuitry is also disclosed which enables access devices and personal computers to adapt voice information between analog voice stream and digital voice packet formats as proves necessary. Routing pathways include wireless spanning tree networks, wide area networks, telephone switching networks, internet, etc., in a manner virtually transparent to the user.

Abstract: A conversion system using a lookup table of adjustment values for converting non-linear, logarithmic pcm codes between attenuated and unattenuated formats. A computer accesses attenuated pcm codes from a compression device, such as that found in the transmit portion of a digital speakerphone, and retrieves an adjustment value from the lookup table using the measured pcm code and a gain code. The gain code corresponds to a gain setting asserted by the computer to a gain device in the transmit portion of the speakerphone. The lookup table is preferably implemented in hardware, such as a ROM, RAM, PLA or similar type device, or is implemented in software or firmware executed by the computer. The retrieved adjustment value is added to the attenuated pcm code to determine the corresponding unattenuated pcm code.

Abstract: A learning aid (100) is employed in learning a target language based upon a known language. The learning aid (100) includes a foldable structure (102) and a plurality of inserts (114, 116, 118). The foldable structure (102) may be placed in any of a plurality of predetermined foldable states and includes a plurality of receiving locations (108, 110, 112), each of which receives one of the plurality of inserts (114, 116, 118). In a transition state, the learning aid (100) presents target language vocabulary (200), corresponding known language vocabulary (204) and corresponding transitions (202) between the known language vocabulary (204) and the target language vocabulary (200). The transitions (202) may include pronunciations of the target language vocabulary (200) such as phonetic pronunciation symbols (402). In a pronunciation state, the learning aid (100) presents only phonetic pronunciation symbols (402).

Abstract: Improved apparatus for a radio communication system having a multiplicity of mobile transceiver units selectively in communication with a plurality of base transceiver units which communicate with one or two host computers for storage and manipulation of data collected by bar code scanners or other collection means associated with the mobile transceiver units. A network controller provides selective interface means to be employed between the host computers and the base transceivers whereby low data rate base transceivers may be utilized with the network controller while spread spectrum or high data rate networked base transceivers may be also utilized. The network controller may allow selection of interface means for three of its ports from its front panel with use of three input keys. The network controller is entirely external to the host computer or computers, and can couple to a variety of commonly encountered host ports.

Abstract: A hierarchical communication system is described in which two wireless local area networks exhibiting substantially different characteristics are employed to link inherently portable or mobile computer devices. A series of radio base stations make up a infrastructure network. The infrastructure network and at least one portable computer device make up the first local area network. The communication on the first local area network is accomplished by spread spectrum frequency hopping communication. A second local area network allows for radio communication between a portable computer device and peripheral devices with built-in transceivers utilized by the portable computer device. The communication in each local area network is controlled by a reservation access communication protocol. The communication protocol facilitates frequency hopping synchronization and supports adaptive data rate selection based upon the quality of communication on the communication channel.

Abstract: A vehicle for transport, fork lift or delivery route operations, for example, includes on-board peripherals which are coupled through a Local Area Network (LAN) into a data system. A LAN data bus provides selective access to the peripherals or data devices such as, for example, a large area display, a keyboard, a printer and a data terminal. The data system controls or provides data on tasks executed by or in connection with the operation of the vehicle. To increase the versatility of the vehicle, the data terminal, multiple data terminals, or any of the other data devices may be removably coupled to the LAN to be operable externally of the vehicle. A mobile mount adapter provides a secure electrical connection of a respective data terminal to the LAN to removably incorporate the data terminal into the data system, and provide a common supply of both data and power to the data device.

Abstract: Interpolation method and apparatus for rendering polygons into a pixel grid. A software driver receives vertices of each polygon and identifies a main slope traversing the vertical extent of the polygon, where the other sides are opposite slopes. The software driver determines initial and incremental width values for width interpolation, rather than edge walking the opposite slopes. The interpolator logic includes a width counter for loading the width value, so that each orthogonal scan line is complete when the width counter reaches terminal count rather than comparing each pixel with the opposite slope. An interpolation procedure thus allows randomly-oriented triangles and other polygons having a main slope, up to two opposite slopes and up to three orthogonal sides to be drawn in a single command.

Abstract: A transceiver apparatus for creating a wireless personal local area network between a computer terminal and one or more peripheral devices. A separate transceiver is connected to the computer terminal and to each peripheral device. The transceivers can be connected to the terminal or peripheral device either internally or externally. A low power radio is used to communicate information between the computer terminal and peripheral devices. Different transceivers can be used for modifying the carrier frequency and power of the local area network. The microprocessor is located inside each transceiver and controls the information flow of the transceiver including the communication protocol which allows each device to know if other devices are communicating, which devices are being communicated to, and selectively address the peripheral devices.