Abstract: Various modem designs are described, along with systems that use the modem designs for communicating data between a large number of remote locations and one or more central locations preferably over CATV. One aspect features a modem having a transmitter which uses a state machine and digital waveform signals stored in a memory to create a modulated signal. Another aspect features a modem having a receiver which uses a digital correlator including an SRAM for detecting a bipolar phase shift keyed signal. Still another aspect features a modem comprising an oscillator circuit having a feedback loop, wherein the feedback loop utilizes a downlink signal, and a protection circuit which prevents a malfunction in the modem from causing system-wide shutdown.

Abstract: A tunable photonic band-gap device is disclosed which utilizes photoresponsive materials and is tunable over a range of wavelengths with the application of light. The device comprises a structure having a plurality of photoresponsive regions arranged in a matrix whereby the behavior of the device in preventing electromagnetic radiation from propagating through the structure may be modified by applying light to the photoresponsive regions. In one embodiment, a photonic band-gap transistor has a light propagation path defined by a plurality of dielectric and photoresponsive rods disposed in a substrate for the routing of a signal through the structure from an inlet to an outlet. The path comprises an input signal path beginning at the inlet, an output signal path terminating at the outlet, and a control signal path which merges with the input signal path to be joined with the output signal path at a common intersection point.

Abstract: A method for unblocking a vacuum collet channel clogged with solder includes moving a solder-clogged collet into contact with a preform of solder, and melting the solder clog and the preform into a single melted mass, cooling the melted mass to solidify it, and moving the collet away from the cooled mass, leaving the clog behind.

Abstract: The present invention provides a game port interface having a second processor interface in addition to an otherwise conventional first processor interface such that a second processor may directly poll the game port interface to detect movement of a joystick device while a first, host processor is in a low power mode. Thus, the second processor may identify movement in the joystick and initiate a wake up sequence in the first, host processor via a communication path between the two processor interfaces. The additional processor interface allows the second processor to poll the joystick without interfering with the normal operation of the joystick. The present invention provides the power savings benefits of maintaining a host processor in a low power mode while at the same allowing another processor which may or may not be in a reduced power mode to detect movement of the joystick and initiate a wake up sequence in the host processor in response thereto.

Abstract: A system and method for generating a coherent reference signal for extracting desired user signals from received signals even after error propagation is underway, are presented. A data symbol preceding a sequence whose relative phases are known is used as an absolute phase reference. Since errors in detection of the phase reference symbol are usually caused by error propagation already underway, the sequence can be used to reacquire the desired signal with merely an absolute phase shift in detected data, which allows accurate differential detection of the desired user signal even in the absence of absolute phase knowledge.

Abstract: The present invention discloses a method for eliminating, or at least minimizing, the locking range variability of laser modules which employ external grating, such as fiber bragg gratings. It has been observed that the coupling efficiency between the laser and its output fiber is a highly variable property of the laser module, causing variations in the laser module's locking range. The laser module's locking range, however, can be readily reset to or near its nominal value by measuring the laser module's coupling efficiency, and then judiciously choosing a grating having a peak reflectivity which compensates for variations in the coupling efficiency by maintaining constant the effective reflectivity Reff of the fiber/grating combination.

Abstract: A preferred embodiment of the cable of the present invention incorporates a core, an outer jacket surrounding the core, and a super-absorbent foam disposed between the core and the outer jacket as well as inside the core. The super-absorbent foam comprises a polyurethane or similar type foam loaded with super-absorbent polymers (SAPs) which exhibit both water-blocking and flame-retarding characteristics. Additionally, the foam preferably is provided with a moisture content of greater than approximately 0 percent, by weight, thereby improving the flame-retarding characteristics of the foam.

Abstract: A system for viewing and monitoring the operation of an embedded processor in which a single computer program, e.g., a Microsoft C/C++3 program, is used to test the scan chain, check the link to the target device, set up the target devices on the scan chain, load the program into the device, run the program, and display the results of the program. The present invention monitors the target processor activity, such as data flow in and out of the target processor, tracking of routines running on the target processor, and the like. Instead of relying on fixed breakpoints, the present invention utilizes breakpoints embedded in the program, enabling the user to use as many breakpoints as desired and to place them and move them wherever they are needed. The breakpoints are defined and set up in the target code (e.g. a diagnostic program) and not by the host. This allows runtime flexibility because the number and location of the breakpoints can be changed easily.

Abstract: Programs which control conventional computerized test systems must be changed when a particular test instrument controlled by the system is changed to a different test instrument. In accord with this invention, the need for such program changes is minimized by utilizing a generic instrument interface for each class of test instruments. A separate specific instrument interface, which corresponds to the specific instrument to be utilized within the general class, is identified in accordance with global variables and a look-up table based upon the general instrument interface called for in the basic test program. A simulator interface is also provided to facilitate the debugging of a basic test program by generating simulated data responses as if an actual test instrument was connected.

Abstract: A bi-directional semiconductor light source is formed that provides emission in response to either a positive or negative bias voltage. In a preferred embodiment with an asymmetric injector region in a cascade structure, the device will emit at a first wavelength (&lgr;−) under a negative bias and a second wavelength (&lgr;+) under a positive bias. In other embodiments, the utilization of an asymmetric injector region can be used to provide a light source with two different power levels, or operating voltages, as a function of the bias polarity.

Abstract: A system and method for discovering association rules that display regular cyclic variation over time is disclosed. Such association rules may apply over daily, weekly or monthly (or other) cycles of sales data or the like. A first technique, referred to as the sequential algorithm, treats association rules and cycles relatively independently. Based on the interaction between association rules and time, we employ a new technique called cycle pruning, which reduces the amount of time needed to find cyclic association rules. A second algorithm, the interleaved algorithm, uses cycle pruning and other optimization techniques for discovering cyclic association rules with reduced overhead.

Abstract: A language recognition methodology is provided whereby any finite-state model of context may be used in a very general class of decoding cascades, and without requiring specialized decoders or full network expansion. The methodology includes two fundamental improvements: (1) a simple generalization, weighted finite-state transducers, of existing network models, and (2) a novel on-demand execution technique for network combination. With the methodology of the invention one or more of the network cascades are formulated as a finite state transducer, and is composed, for a selected portion of the network, with a next successively higher level of the network cascade to prescribe a mapped portion of that next successively higher level corresponding to the portion of the network cascade selected to be expanded.

Abstract: A digital portable telephone is configured without the complex circuitry normally required for its base unit and handset unit to switch between transmit and receive states while frequency hopping in a frequency hopping system. The architecture for this digital portable telephone provides improved performance over that of other digital portable telephones by combining the frequency hopping spread spectrum technique with other spread spectrum techniques in communications between the handset unit and the base unit. Specifically, delta modulation and a redundant transmission of the signal are the other forms of signal spreading that are employed. Such signal spreading advantageously achieves additional processing gain. Another attractive attribute of this architecture is a high level of immunity to interference from other portable telephones also operating in the same frequency hopping band.

Abstract: An automated “tuning” system is disclosed that utilizes the known tuning curve (on an approximation thereof) to control the tuning process. In particular, the tuning curve is transformed (if necessary) into a quadratic with a local maximum, where the maximum is associated with the optimum tuning value. In one embodiment, the tuning system of the present invention may be used to provide alignment between optical components. The system may be organized to recognize “backlash” in the tuning process and perform additional tuning adjustments to overcome this backlash. Each tuning curve may be one-dimensional and a set of such curves used to provide for an N-dimensional tuning.

Abstract: An optical detector is provided including a substantially annular metallic ring positioned on either side of an active (i.e. intrinsic) region of the optical detector to minimize optical crosstalk. Optical crosstalk originates from adjacent optical sources (e.g., VCSELs) emitting light toward the direction of the optical detector. The metallic ring prevents the light which propagates substantially parallel to a base of the optical detector from reaching the active region of the optical detector.

Abstract: A demounting apparatus is described which releases semiconductor work pieces from an adhesive support structure. The demounting apparatus includes a conduit with a pair of opposed openings. A support structure is placed over one of the openings with a work piece mounted on a lower surface thereof. A vacuum is exerted on the conduit through a constricted outlet, thereby creating a pressure differential. The lower pressure within the demounting apparatus causes the support structure to elastically deform, thereby reducing its adherence on the work piece. The work piece is dislodged from the support structure and caught by a cushion positioned in the other opening. The cushion is pushed inwardly by the pressure differential. Other structures for releasing the work piece are also disclosed.

Abstract: An enclosure protects electronic equipment from physical contact and electromagnetic interference. The enclosure includes a base portion which is attachable to a circuit board and which surrounds all sides of the electronic equipment. A cover is attachable to the base in order to cover the top of the electronic equipment. The cover is attachable to the base by snap-in tangs formed on the base which cooperate with projections formed on the cover. The base is attachable to the circuit board by snap-in fasteners formed on the base. The base and the cover are made of a material which reflects and/or absorbs EMI. The EMI shielding enclosure protects the electronic equipment and allows access to the electronic equipment for replacement or repair without having to take the time to manipulate separate mechanical fasteners.

Abstract: An alignment sleeve in accordance with the present invention interconnects optical ferrules of dissimilar size and axially aligns the ferrules with precision in a mating relationship so as to reduce loss in the optical signal passed from one ferrule to the other. A plurality of lands on the inner wall of the alignment sleeve contact and hold the respective ferrules in a predetermined axial relationship with respect to one another. The alignment sleeve comprises a compliant material which conforms to slight variances in the diameters of the ferrules received by the alignment sleeve. The alignment sleeve advantageously provides for the interconnection of ferrules of dissimilar size with precise alignment of their respective cores, which reduces the connection loss of the two ferrules. The alignment sleeve can be mass produced using injection molding techniques. The mold utilized in the injection molding process includes a precision core pin that can be manufactured using a precision grinder or lathe.

Abstract: The system for direct suppressed ringing access of a subscriber line enables the service provider to access subscriber lines from any location, as long as the incoming call is identified and authenticated as a suppressed ringing access call. The central office switch can maintain a list of predefined line numbers that are used by an authorized service provider to perform the suppressed ringing access function. Thus, a call origination on one of these lines is automatically validated as a suppressed ringing connection call. Alternatively, the suppressed ringing connection is requested by the inclusion of a predefined code in the dial string and the central office switch automatically authenticates the identity of the service provider.

Abstract: An electrical connector comprises connector contacts having a metal base and a surface finish layer over the base, the surface finish layer being a composite of an electroplated precious metal composition and wear resistant particles dispersed therein. In the preferred embodiment, the precious metal layer is a PdCo alloy and the wear resistant particles are sub-micron sized lubricating particles, e.g. polytetrafluoroethylene particles and a flash coat of gold is provided over the composite layer.