Abstract: A fastener for detachably coupling a housing, such as a battery pack, to an appliance, such as a wireless terminal, is disclosed. In use, the fastener is disposed in a housing. When a user applies a force to the fastener to release the housing from the appliance, the fastener rotates about an axis, causing an engagement feature of the fastener to rotate away from the appliance, thereby decoupling the fastener from the appliance. The fastener includes a biasing member which provides a restoring force that keeps the fastener coupled to the appliance in the absence of a decoupling force. In some embodiments, the fastener includes various features suitable for reducing stress that accumulates in the biasing member as it rotates during decoupling. Such features include a stress-reducing surface, and an offset between the stress-reducing surface and the axis of rotation.

Abstract: Automatic bias setting circuits for multiple quantum well (MQW) diodes and optical modulators generally are described. Both digital and analog circuits are provided and techniques for utilizing such circuits for monitoring and controlling optical modulator signal quality are disclosed. In one approach, a desired modulation voltage range is determined. A bias voltage is stepped from a first predetermined voltage up to a second predetermined voltage. A maximum differential photocurrent is determined and the bias voltage corresponding to that photocurrent is then employed so that optimal optical modulator signal quality is achieved. An advantageous application of this technique is in wavelength division multiplexed (WDM) systems in which different optical modulators are operating at different wavelengths. In such a system, a different voltage bias will typically be determined for each optical modulator.

Abstract: An electronic price label (EPL) system including an EPL for attracting customers which uses a noisemaker to make noise during special promotions. The system includes an EPL associated with an item including a noisemaker, and an EPL computer which transmits a command to the EPL to activate the noisemaker during a special promotion of the item. The EPL computer may also transmit a command to display a promotional message to the EPL.

Abstract: An index generator and query expander for use in information retrieval in a corpus. A corpus is provided as an input to an inflectional analyzer, which produces a lemmatized corpus having base forms and associated inflections for each word in the original corpus. The lemmatized corpus is provided as an input to a disambiguator, which performs part of speech tagging and morpho-syntactic disambiguation to produce a disambiguated corpus. The disambiguated corpus is provided as an input to a derivational generator, which produces an expanded corpus having all possible valid derivatives of each word of the disambiguated corpus. The disambiguated corpus is provided as an input to a transformational analyzer, using a grammar and a metagrammar for analyzing syntactic and morphosyntactic variations to conflate and generate variants, producing an index to the corpus having a minimum of variants. Alternatively, a query expander is provided utilizing similar techniques.

Abstract: A hierarchical instruction set architecture (ISA) provides pluggable instruction set capability and support of array processors. The term pluggable is from the programmer's viewpoint and relates to groups of instructions that can easily be added to a processor architecture for code density and performance enhancements. One specific aspect addressed herein is the unique compacted instruction set which allows the programmer the ability to dynamically create a set of compacted instructions on a task by task basis for the primary purpose of improving control and parallel code density. These compacted instructions are parallelizable in that they are not specifically restricted to control code application but can be executed in the processing elements (PEs) in an array processor. The ManArray family of processors is designed for this dynamic compacted instruction set capability and also supports a scalable array of from one to N PEs.

Abstract: A modulated backscatter communication system (e.g., an Electronic Shelf Label (ESL) system) includes a central node (e.g., a ceiling node) and one or more remote nodes (e.g., ESL tags). The central node transmits a downlink radio signal which is reflectively modulated at a remote node to produce a modulated reflected radio signal. At the remote node, a precise-frequency subcarrier signal is modulated with an uplink information signal to produce a modulated signal which is used to produce the modulated reflected radio signal. At the central node, the modulated reflected radio signal is received, detected and narrowband filtered to obtain the modulated subcarrier signal which is then demodulated to obtain the uplink information signal, with great immunity to close to carrier downlink radio noise and fluorescent light backscatter interference.

Abstract: An electronic price label (EPL) system including groups of electronic price labels and method of managing the groups which facilitate group definition, assignment of EPLs to groups, assignment of items to EPLs, and assignment of prices to items. The system includes a plurality of EPLs arranged in a single line of bays within a sign to define a group. A computer coupled to the EPLs defines the group, assigns the EPLs to the group, and assigns item identification numbers and prices to the EPLs. A storage medium stores group definition information, EPL assignments to the group, and item assignments to the EPLs. The storage medium additionally stores a price identifier, which is preferably added to the item identification numbers to form modified item identification numbers.

Abstract: An Erbium doped fiber amplifier (EDFA) is placed in a laser cavity to clamp the gain of the amplifier. The laser cavity is preferably formed to minimize the effects of relaxation oscillations and of spectral hole burning. In a preferred embodiment, the laser cavity supports a lasing wavelength which makes the saturation energy at the laser wavelength less than that at the signal wavelengths. In an erbium doped fiber implementation, the laser wavelength is shorter than that of the signal wavelengths and is separated from them by no more than approximately 75% of the width of the spectral hole. The compounding of relaxation oscillations may be substantially eliminated by varying the length of the fiber within each laser cavity within a system to change the photon round-trip time within each cavity.

Abstract: A cellular telephone system including a cellular telephone operable to perform functions programmed at a central location. The telephone transmits a code to a central computer, which then executes the function associated with the code. Functions include, for example, establishing a telephone connection between the telephone and a called number, providing access to voice mail, callback paging, and programming. The central computer may be programmed to associate new functions with particular codes. The telephone system also includes a base station for charging a battery of the cellular telephone, for low-battery or battery-free operation of the cellular telephone, and for programming the telephone or the central computer.

Abstract: An electronic price label (EPL) including a noisemaker to assist in locating the EPL. Besides a noisemaker, the EPL includes processing circuitry which activates the noisemaker upon receipt of a command from a computer. A method for locating an EPL includes the steps of providing a noisemaker within the EPL, and transmitting a first signal to the EPL including a command to activate the noisemaker from a computer. The method may additionally include the steps of providing a plurality of receiving antennae, determining locations of the receiving antennae, transmitting a second message to the EPL by a computer coupled to the receiving antennae, listening for a third message from the EPL in response to the second message by the computer, determining signal strengths of the third message at each of the receiving antennae, and determining an estimate of the location of the EPL from the signal strengths by the computer.

Abstract: A method of minimizing power consumption within an electronic price label (EPL) which conserves battery life. A time period for removing power from a transceiver within the EPL is determined by a computer from price change frequency data. A message to control circuitry within the EPL is sent by the computer as soon as possible following a change in price displayed by the EPL. The message includes a command to remove power from the transceiver and the power down time period. Power is removed from the transceiver by the control circuitry. The control circuitry counts until the power down time period is exhausted. Power is applied to the transceiver by the control circuitry when the power down time period is exhausted. Finally, a first time within the control circuitry is synchronized by the control circuitry to a second time indicated by the computer after the power down timer period is exhausted and before any additional message is sent to the EPL.

Abstract: A system and method of determining price differences between price files which minimizes the possibility that an incorrect price is displayed by an electronic price label (EPL). The system includes a computer which reads the first and second price files, compares the prices for the items in the first and second files, and identifies predetermined items having different prices in the first and second files. The computer is preferably an EPL computer. Once a price discrepancy is identified, it may be logged and acted upon in accordance with rules established by an operator.

Abstract: An electronic price label which produces a wider vertical viewing angle than previous electronic price labels for improved reading of prices at different shelf heights. The electronic price label includes a liquid crystal display for displaying character information, including price information, along a substantially horizontal direction. The liquid crystal display includes a number of polarizers which produce a maximum vertical viewing angle and a maximum horizontal viewing angle, wherein the maximum vertical viewing angle is greater than the maximum horizontal viewing angle.

Abstract: A method of sending information to an electronic price label (EPL) for display which requires only one message to be sent to the EPL. Second information is recorded in response to an operator request to change first information displayed by the EPL. The second information includes predetermined characters within a group of characters including numerals 0-9, letters A-Z, blanks, and predetermined symbols. The second information is encoded into a word using a number of translation tables. The word is sent to the EPL in a single wireless message. The word is received by the EPL. The word is decoded by the EPL using the translation tables. Finally, the second information is displayed by the EPL.

Abstract: An array processor includes processing elements arranged in clusters which are, in turn, combined in a rectangular array. Each cluster is formed of processing elements which preferably communicate with the processing elements of at least two other clusters. Additionally each inter-cluster communication path is mutually exclusive, that is, each path carries either north and west, south and east, north and east, or south and west communications. Due to the mutual exclusivity of the data paths, communications between the processing elements of each cluster may be combined in a single inter-cluster path. That is, communications from a cluster which communicates to the north and east with another cluster may be combined in one path, thus eliminating half the wiring required for the path. Additionally, the length of the longest communication path is not directly determined by the overall dimension of the array, as it is in conventional torus arrays.

Abstract: An interactive electronic drum system and training techniques suitable for use in a coin-operated environment such as an arcade are described. Electronic drum pads, audio speakers, a visual display, training lights and an overall control system are combined to simulate the excitement of a live drum or inactive musical jam session for a user. Positive feedback and, as necessary, instructive aid are provided to make the experience a positive one for both the novice and the expert player. Learning and playing a musical instrument becomes an intuitive, exciting experience and not a boring chore to be endured. Players can simulate the experience of playing in a rock band before a live and appreciative audience. In short, this interactive electronic drum system makes drums and the jamming experience widely accessible to the public.

Abstract: A price change verification system and method for an electronic price label (EPL) system which verifies that price changes have been implemented by associated EPLs. A storage medium contains a record associated with the EPL. The record includes a price change time and a new price for the EPL. An EPL computer sends a price change message containing the new price to the EPL at a time substantially equal to the price change time. The EPL computer additionally verifies that the EPL is displaying the new price by reading the record to determine the price change time, obtaining a currently displayed price from the EPL, and comparing the currently displayed price to the new price.

Abstract: A system and method of locating a wireless device which relies on signal strength measurements and the known positions of receiving sensors. The system includes a number of transceivers each including a transmitter which transmits a first signal to the wireless device, a plurality of receivers including a plurality of sensors and at least one signal strength determining circuit for determining signal strengths of second signals received by the sensors, and a control circuit for controlling transmission of the first signal and reception of the second signals. A storage medium contains the locations for each of the sensors. A computer coupled to the control circuit instructs the control circuit to transmit the first signal and determines a location of the wireless device from the signal strengths and from the locations of the sensors.

Abstract: An electronic price label (EPL) mounting device and method which allows an EPL to be mounted on a shelf at a number of viewing angles. The device includes a first portion coupled to the shelf, and a second portion which retains the EPL and which is rotatably coupled to the first portion. The device may additionally include a retainer for securing a sign to the second portion.

Abstract: An electronic price label (EPL) system which is capable of displaying price information in terms of a plurality of different currencies. The system includes an EPL and a computer. The EPL includes a display, and a control circuit which causes the display to display price information based upon a plurality of different currencies. The computer sends messages to the EPL instructing the EPL to display predetermined price information based upon a predetermined currency.