Abstract: A tunable semiconductor laser comprises a gain section having an MQW active region, a uniform pitch grating DFB region, and first waveguide. A composite reflector, including a second MQW region and a second waveguide, forms a cavity resonator with the DFB region. A tuning voltage applied to the composite reflector induces refractive index changes, thereby allowing the center wavelength to be altered.

Abstract: We describe a method for solving the joint problem of optimal routing and optimal bandwidth allocation in a network that supports plural subnetworks and plural communication services. Our method involves, for each source-destination pair communicating via a given subnetwork and a given class of service, determining a traffic rate to be offered to each of a set of permissible routes between that source and that destination, in the given subnetwork and service class. Our method further involves allocating a respective bandwidth to each link of each subnetwork. Significantly, the determinations of traffic rate to be offered, and the allocations of bandwidth to respective links of subnetworks, are performed in a mutually responsive manner.

Abstract: A known training sequence of binary, pseudo random signals, PN, is received over the channel and correlated with a modified pseudo random sequence PN−1 in which the zeros of the known sequence PN have been mapped to −1. A transform of the correlator output will be observed to contain strong tones that indicate the degree of frequency offset. To facilitate synchronization in the presence of an unknown amount of frequency offset, the received signals may be rectified and the correlation step performed with the absolute value of the incoming signal to obtain new output samples. When the frequency offset is small its measurement is facilitated by modulating the incoming signals with a known, comparatively large frequency offset, before the correlation step to make sure that the overall frequency offset occurs around a frequency that is an integral multiple of the symbol rate divided by the number of symbols in the pseudo random sequence.

Abstract: A titanium-tantalum barrier layer film for use in conjunction with an interconnect film such as copper and a method for forming the same provides a relatively titanium rich/tantalum deficient portion adjacent the interface it forms with a dielectric film and a relatively tantalum rich/titanium deficient portion adjacent the interface it forms with a conductive interconnect film formed over the barrier layer film. The titanium rich/tantalum deficient portion provides good adhesion to the dielectric film and the tantalum rich/titanium deficient portion forms a hetero-epitaxial interface with the interconnect film and suppresses the formation of inter-metallic compounds. A single titanium-tantalum film having a composition gradient from top-to-bottom may be formed using various techniques including PVD, CVD, sputter deposition using a sputtering target of homogeneous composition, and sputter deposition using multiple sputtering targets. A composite titanium-tantalum film consists of two separately formed films.

Abstract: A wavelength conversion apparatus and method uses four wave mixing of a first wavelength and a control wavelength in an optical fiber to convert the first wavelength to a desired wavelength. Four wave mixing is produced by operating the optical fiber at a predetermined input power density and by using a fiber length which provides substantial Raman gain. The first wavelength is converted to a higher wavelength by using the higher wavelength four wave mixing signal and converted to a lower wavelength by using the lower wavelength four wave mixing signal.

Abstract: In a cellular telephone system, as the strength of the signal between a cell site and a mobile unit weakens in the absence of another cell site to hand off the mobile unit to, the mobile unit user is warned of the impending loss of the call before it occurs. This allows the user sufficient time to take precautionary steps such as moving or re-orienting the hand-held mobile unit to compensate for the loss of signal strength and maintain integrity of the communications link. The mobile unit user is warned of a signal level reduction below a predetermined threshold by means of an audible tone emitted by the mobile unit's earpiece prior to loss of a call in progress.

Abstract: A system and method for determining the location of faults in a telephonic distribution system where each endpoint in the system has an associated verification code. The endpoints are polled and the response is compared to a corresponding verification code in memory. When the response does not match the verification code in memory the result is included in an endpoint map. An analysis is then performed to identify faulty elements in the system which are reported with their geographical location coordinates.

Abstract: The present invention is directed to a mounting clip for electronic components and, more specifically, to a component retention spring clip for securing electronic components to an electronic device support such as the leg of a heat sink. In one embodiment the component retention clip is comprised of a resilient strip that has an arcuate portion and first and second ends. The resilient strip is configured to encompass an electronic component and an electronic device support adjacent to the electronic component. The arcuate portion of the component retention clip contacts a portion of the electronic component, thereby partially supporting the electronic component against the electronic device support. Located at the first end of the resilient strip is a first latch configured to cooperatively engage a corresponding second latch located at the second end and retain the electronic component on the electronic device support.

Abstract: Video processing apparatus for supporting a video conference includes a processor/server, a conference bridge and a network of terminals, each terminal equipped with at least a video camera, display and a user input device such as a mouse. A user may select a conference context including a conference location, type (setting) and purpose that may be different from the selection of another conferee. The user may select a conference location and type, view a conference according to a default selection or design their own location and type in advance of the conference. The user also may select personal requirements and signal the need for various resources prior to and in real time during a conference. At the conference bridge, each conferee that joins a video conference is assigned a position at a conference setting of their selected context, for example, a round table or U shaped table generated as a video graphic.

Abstract: In a wireless data network, such as a General Packet Radio Service (GPRS) network, a transmitter uses one of k coding/modulation schemes for transmitting data. The transmitter initially selects a coding/modulation scheme, C, as a function of carrier-to-interference ratio (C/I) measurements. The transmitter then calculates the number of blocks, B, required to transmit a number of data packets, D, using the coding/modulation scheme C. In addition, the transmitter calculates the number of blocks required to transmit the number of data packets, D, for each coding/modulation scheme that is stronger than the selected coding/modulation scheme C. The transmitter finally selects that coding/modulation scheme that results in transmitting the number of data packets D in B blocks using the strongest coding/modulation scheme. As a result, each block is transmitted using the strongest coding/modulation scheme available.

Abstract: A fiber storage system includes one or more splice holder assemblies and one or more fiber routing devices. The splice holder assembly has a sleeve in the shape of a closed figure having a plurality of substantially flat sides or a ring. The sleeve has a plurality of holes on its sides. At least one splice holder is mounted on the side walls of the sleeve, near one or more of the holes. The fiber routing device includes a sleeve in the shape of a closed figure having a plurality of substantially flat sides or a ring, and a plurality of troughs attached to an outer surface of the top portion of the sleeve. The splice holder assemblies may be stacked on top of each other, or on top of the fiber routing devices. The fiber routing devices may be stacked on top of each other, or on top of the splice holder assemblies. The stack of splice holder assemblies and fiber routing devices form a pedestal for routing and terminating optical fibers.

Abstract: A wireless communications system (110) with increased privacy. The system (110) transmits an encrypted signal between a base station (112) and a wireless terminal (122). In the forward channel, the base station (112) includes an encryptor (130) with a long code mask generator (200) that generates a rolling long code mask. The wireless terminal (122) similarly includes a decryptor (164) with a long code mask generator (208) that creates a rolling long code mask.

Abstract: In a communications terminal that has an image reject mixing arrangement, a compensation system provides compensation for phase and amplitude imbalances, which are caused by a demodulating local oscillator employed in the communications terminal. The image reject mixing arrangement comprises a radio-frequency (RF) mixing stage including an in-phase and a quadrature phase branch, which is configured to receive a radio frequency signal and down convert the radio frequency signal to in-phase and quadrature phase intermediate frequency (IF) signals. It also includes a phase splitter unit coupled to the radio-frequency (RF) mixing stage and configured to provide an in-phase local oscillator signal and a quadrature phase local oscillator signal to the RF mixing stage. The phase splitter causes an amplitude imbalance signal &Dgr; and a phase imbalance signal &phgr; to be generated in the in-phase and quadrature phase branch of the RF mixing stage.

Abstract: A preferred embodiment of the cable of the present invention incorporates a core, an outer jacket surrounding the core, and a commercially available super-absorbent fibers disposed between the core and the outer jacket as well as inside the core. The fibers may also be applied to a tape to be provided between the core and the outer jacket. The tape incorporates a first layer and super-absorbent fibers, with the super-absorbent fibers being applied to the first layer. Preferably, the first layer is formed of spun bonded non-woven polyester material, nylon spun bonded fabric, non-woven glass, polypropylene melt blown non-woven fabric, polyurethane spun bonded fabric, or TCF cellulose fabric, among others. Additionally, the fibers preferably are provided with a moisture content of greater than approximately 0 percent, by weight, thereby improving the flame-retarding characteristics of the tape.

Abstract: A wireless message notification system includes a message processing unit which also serves as a battery recharger for a portable wireless device. The message processing unit includes a receiver for receiving a wireless data message sent by a central service facility and a docking station. While the wireless device is recharging in the docking station, the message processing unit compares the messages that it has received from the central service facility against the messages received by the wireless device. If the message processing unit has received additional messages, the additional messages are downloaded to the wireless device for the user to review.

Abstract: A multiple description (MD) joint source-channel (JSC) encoder in accordance with the invention encodes n components of an image signal for transmission over m channels of a communication medium. In an illustrative embodiment which uses statistical redundancy between the different descriptions of the image signal, the encoder forms vectors from transform coefficients of the image signal separated both in frequency and in space. The vectors may be formed such that the spatial separation between the transform coefficients is maximized. A correlating transform is then applied, followed by entropy coding, grouping as a function of frequency, and application of a cascade transform. In an illustrative embodiment which uses deterministic redundancy between the different descriptions of the image signal, the encoder may apply a linear transform, followed by quantization, to generate the multiple descriptions of the image signal.

Abstract: In a server system having a predetermined total bandwidth providing data files to a plurality of clients in response to requests received from the clients, a method for providing admission control comprises the steps of allocating a plurality of channel partitions to a plurality of channel groups such that each channel group includes one or more of the channel partitions. The system then obtains a channel group number based on the length of the data file requested by one of the clients and transmits the requested data file when a channel group corresponding to the obtained channel group number contains a vacant channel partition.

Abstract: A time slotted system capable of switching between two or more antennas during the guard times of the time slots. Switching between antennas during the guard time of the time slots eliminates any disturbance to the user, since it eliminates any loud noise, or popping that can occur during the switching between antennas. The beamwidth of each of the antennas is narrower than needed to cover a sector of a cell of the system, increasing the size of the cell due to the larger gain of the narrower beamwidth antenna elements. The system also includes a scanning radio for determining the optimal signal amongst the signals received on the antennas, and a switch for coupling the antenna receiving the optimal signal to a receiver system. In one embodiment of the invention the optimal signal is based on the information content of the signal, such as the signal's bit error rate.

Abstract: Received channels are grouped into channel groups in which each channel group includes channel members with commensurate signal parameter values to enhance performance of a wireless communications system. A data processing system establishes boundaries of each channel group to achieve an approximately equivalent quality of service (e.g., blocking rate) for each channel group based on the probabilities of occurrence of measured signal parameter values.

Abstract: The effect of polarization mode dispersion that an optical signal experiences as it propagates through an optical transmission fiber is compensated for at a receiver using a birefringent compensator, in which a distortion analyzer repeatedly examines the signal outputted by the compensator and causes the compensator to reduce the effect of such polarization mode dispersion based on the results of such examination.