Abstract: Two devices having a latching mechanism of the present invention can be mounted back to back within a single mounting hole in a mounting surface. Each latching mechanism has two or more prongs designed such that they do not interfere with the prongs of another device mounted within the same mounting hole from the opposite side of the mounting surface. In one embodiment, the present invention can be implemented as a retainer for retaining wires, cables, and cables for telecommunications applications. In a preferred embodiment, each retainer prevents access from its side of the mounting surface to the other retainer mounted from the other side of the mounting surface. As such, the present invention provides a security feature for the assembly.

Abstract: A microcell architecture includes a macrocell base station capable of receiving signals from and transmitting signals to at least one microcell base station provided within a first predefined geographic area. The macrocell base station includes circuitry for converting downstream channel unit information to downstream baseband channel information and for modulating and transmitting the downstream baseband channel information. It also includes circuitry for demodulating received upstream baseband channel information and for converting the received baseband channel information to upstream channel unit information. Also provided is at least one microcell base station, provided within the first predefined geographic area, for communicating with wireless terminals within a second smaller predefined geographic area within the first predefined geographic area.

Abstract: In an antenna having a conductor of a length L and a dielectric material with a dielectric constant .epsilon..sub.r1 contacting the conductor, a matching dielectric layer .epsilon..sub.r2 less than .epsilon..sub.r1 matches the dielectric constant to free space. Preferably .epsilon..sub.r2 =.sqroot..epsilon..sub.r1 , L=.lambda..sub.o /(2.sqroot..epsilon..sub.r1 ). The depth d of the second dielectric is a quarter wavelength in the matching layer. Multiple matching layers with successively decreasing dielectric constants forms embodiments. In one embodiment the resonant conductive arrangement is a microstrip patch antenna with the dielectric material supporting a patch and matching layer covering the dielectric material.

Abstract: Techniques for maintaining an approximate histogram of a relation in a database, in the presence of updates to the relation. The histogram includes a number of subsets, or "buckets," each representing at least one possible value of an attribute of the relation. Each of the subsets has a count associated therewith indicative of the frequency of occurrence of the corresponding value of the attribute. After an update to the relation, the counts associated with the subsets are compared to a threshold. If the count associated with a given subset exceeds the threshold, the given subset is separated at its median into two separate subsets. After the separation operation, the two subsets with the lowest counts are combined such that a constant number of subsets are maintained in the histogram, if the total combined count of the subsets does not exceed the threshold. If no two subsets have a total combined count which does not exceed the threshold, the histogram is recomputed from a random sample of the relation.

Abstract: An asymmetrical half-bridge converter, a method of operating the same and a power supply that incorporates either the converter or the method. In one embodiment, the converter includes: (1) a power transformer that receives asymmetrical AC input power into a primary winding thereof via an input capacitor, the asymmetrical AC input power inducing a DC bias current in a secondary winding of the power transformer and (2) first and second serially-coupled output inductors coupled across the secondary winding and having parasitic resistances associated therewith that are independently selectable to attenuate the DC bias circuit in the secondary winding.

Abstract: An expandable local area hub network is provided by the present invention. The network comprises a plurality of hubs interconnected for direct communication. Each hub includes a plurality of ports for interfacing with remote stations, wherein the remote stations make requests that packets be transmitted on a memory coupled to the plurality of hubs. In use, one of the plurality of hubs is designated as a temporary controlling hub having controlling access to the memory bus to transmit packets on the memory bus. The temporary controlling hub relinquishing access to the memory bus when the temporary controlling hub has no requests to dispatch a packet on said memory bus.

Abstract: Apparatus and method for eliminating cross conduction of self-driven synchronous rectifiers in power converters caused by non-idealized ringing of parasitic capacitances and inductors. In an exemplary embodiment, the apparatus includes synchronous rectifiers or some hybrid topology having at least one synchronous rectifier coupled to a damping circuit having at least one switching device. The switching device is activated (ON) at a time when at least one of the synchronous rectifiers is supposed to remain inactive (OFF). Accordingly, when the switching device is ON, the device effectively dampens any ringing present at the synchronous rectifier that may cause the rectifier to inappropriately transition ON. The damping circuit of the present invention utilizes the same signals present to control the synchronous rectifier(s) and requires no additional control circuitry. Additionally, the damping circuit dramatically improves the efficiency of self synchronous power converters and is topology independent.

Abstract: A self-steering antenna apparatus for receiving and transmitting electromagnetic signals, includes a plurality of antennas for receiving and emitting electromagnetic signals and a plurality of receivers for processing the received electromagnetic signals. Each one of the plurality of receivers corresponds to a respective one of the plurality of antennas. Each receiver provides signal strength information indicating a signal strength of the electromagnetic signal received by the corresponding antenna. A comparator compares the signal strength information provided by each receiver, and determines which of the antennas is receiving the strongest electromagnetic signal. Switching circuitry switches the received electromagnetic signals and the signals to be emitted, based on the comparison performed by the comparator, the switching circuitry selecting one of the plurality of antennas to emit and receive the electromagnetic signals based on the comparison.

Abstract: A Multi-Code (MC) Code Division Multiple Access (CDMA) receiver receives N (where N.gtoreq.1) encoded signal channels over multiple air signal paths. The N signal channels are encoded using a properly chosen subset of Walsh codes based on a Walsh-Matrix, W.sup.M, where M is a power of two. In the disclosed MC-CDMA receiver, a timing correlator means recovers the timing and control signal for the N signal channels received over any particular signal path; a FWHT circuit together with a second correlator means decodes all of the N signal channels.

Abstract: Methods and apparatus for a language model and language recognition systems are disclosed. The method utilizes a plurality of probabilistic finite state machines having the ability to recognize a pair of sequences, one sequence scanned leftwards, the other scanned rightwards. Each word in the lexicon of the language model is associated with one or more such machines which model the semantic relations between the word and other words. Machine transitions create phrases from a set of word string hypotheses, and incrementally calculate costs related to the probability that such phrases represent the language to be recognized. The cascading lexical head machines utilized in the methods and apparatus capture the structural associations implicit in the hierachical organization of a sentence, resulting in a language model and language recognition systems that combine the lexical sensitivity of N-gram models with the structural properties of dependency grammar.

Abstract: The specification describes a process and apparatus for monitoring and controlling the ellipticity of preform tubes during Modified Chemical Vapor Deposition. In response to computer generated signals from the monitoring device, the tube collapse rate is adjusted dynamically by locally changing the temperature of the glass tube, or by changing the physical force acting to collapse the tube.

Abstract: The specification describes a MCM IC package with improved RF grounding. The package has at least one RF IC chip bonded to an interconnect substrate and the substrate is interconnected to an intermediate printed wiring board (IPWB). The IPWB is interconnected in turn to a system printed wiring board (SPWB). The RF IC chip is metallized on the backside, and is flip chip bonded directly to the SPWB thereby eliminating two intermediate interconnections and reducing the impedance of the interconnection between the RF chip and the SWBP.

Abstract: A ground voltage reduction device is connected between a neutral reference node and a ground node defined by two bypass capacitors of a blocking circuit. The ground voltage reduction device senses the voltage difference between the neutral reference node and the ground node and drives the ground node to reduce the voltage difference between a voltage of the ground node and a voltage of the neutral reference node.

Abstract: A comparator with output that responds quickly to changes in input. The comparator is made up of three stages, an input sampling network, a first amplifier stage, and a second amplifier stage. The input sampling network interfaces the two voltage levels that are to be compared with the first amplifier stage. The first amplifier stage then generates a low level signal that is dependent on the relative levels of the two inputs and passes the low level signal to the second amplifier stage. The second amplifier stage amplifies the output of the first amplifier stage to a usable level. Superior response time is achieved through by dividing the input sampling network into two stages, an input stage and an offset stage, and decoupling the two stages during offset cancellation.

Abstract: A modulator having low insertion and a broad operating bandwidth is disclosed. The modulator has a movable membrane that is spaced from a substrate. The reflectivity of the movable membrane, and the reflectivity of the subtrate/gap interface are unequal. In particular, relative to the membrane, the substrate has a lower reflectivity. Device finesse is dictated by the lower reflectivity "mirror," i.e., the substrate. The substrate configuration thus provides a broad operating bandwidth while the higher reflectivity membrane provides low insertion loss.

Abstract: Timing recovery circuits, automatic gain control circuits and the like, employ a so-called vector tracking filter (VTF) in conjunction with other timing recovery techniques. The VTF includes a complex filter with a time constant so long that it might be considered a leaky integrator. In operation, the VTF builds up an average vector (timing (gain estimate vector) having a direction that is the average of the estimated timing (gain) error, which is stored in the VTF. When an arbitrary timing (gain) correction is made, to the incoming signal, this causes a rotation of the timing (gain) estimate vector. In order to track this rotation, a comparable rotation is made to the stored timing (gain) estimate vector. This allows the stored timing (gain) estimate vector to build up, and at any time the stored timing (gain) estimate vector will be the same as if the current incoming phase had been constant for all previous time.

Abstract: A method of improving the yield and achievable tolerances of integrated circuits by obtaining surface measurements of non-reflective soft mounting films used in integrated circuit manufacture. The non-reflective surface of a mounting film is first rendered reflective by applying a reflective wafer atop the film surface. This reflective test wafer, which is highly plano-parallel and preferably has a thickness less than that of the ultimate product wafer, is applied to the mounting film to be measured via direct pressure whereby the reflective test wafer conforms to and takes on the surface characteristics and contours of the film. The formerly non-reflective surface of the mounting film is thereby rendered effectively reflective and thus susceptible to optical profiling and graphical and numerical recordation by a computerized interferometer in accordance with well-known techniques.

Abstract: Calls redirected off-net, which includes call forwarding and call coverage, is provided at the switch to which the call is initially directed (the principal party's switch), by monitoring the redirected off-net connection with a call classifier and listening for the appearance of ringback tone and the appearance of voice frequency energy. The call is allowed to be completed to the off-net covering end-point if voice frequency energy is detected before ringback tone appears or if voice frequency energy appears within a predetermined time-out interval. If ringback tone continues beyond a time-out interval, if voice-frequency energy is not detected within the time-out interval, or if a call progress tone other than ringback is detected, further processing of the call is continued at the principal party's switch to determine if another covering point is listed. If no other coverage point is listed, monitoring of the call continues until the calling party hangs up.

Abstract: An improved voice activity detection system and method is provided for use in speakerphones and other voice activated systems. To facilitate switching between various operating modes, the voice activity detection scheme utilizes a new voice energy term which is based on an integral of the absolute value of a derivative of a speech signal. Voice activity is detected during a silence mode by comparing a first ratio of a current voice energy value to a background noise value with a voice activity threshold value. Voice activity is detected when the first ratio is greater than the voice activity threshold value. Another step involves identifying a direction of the voice activity during a transmit and receive mode by comparing a second ratio of a transmit path voice energy value to a receive path voice energy value with a transmit threshold value and a receive threshold value. When the second ratio is greater than the transmit threshold value, voice activity is present in the transmit path.

Abstract: The input branch of the current mirror is responsive to a single input signal current and each output branch of the current mirror mirrors the input signal current to produce an output current proportional to (e.g., substantially equal to) the input signal current. In one embodiment, the input branch has an input mirror MOS transistor connected to a threshold voltage generator, the output branch has an output mirror MOS transistor connected in cascode to an output cascode MOS transistor, and all of the transistors operate in saturation. The threshold voltage generator may be implemented in different ways, including using four MOS transistors forming two current paths, such that, in one current path, two transistors have channel constants of X and 4X, respectively, and, in another current path, two transistors both have channel constants of A, which may be different from X.