Abstract: An approach for synchronizing operation of a first communications terminal with operation of a second communications terminal involves establishing a communications link between the first communications terminal and the second communications terminal, the communications link being defined by a communication standard; and synchronizing a first clock coupled to the first communications terminal with a second clock coupled to the second communications terminal by receiving a time standard signal into the first communications terminal independently of the communication standard. This approach can be implemented using a first clock; a first communications terminal coupled to the first clock; a second clock; a second communications terminal coupled to the second clock; a communications link defined by a communication standard; and a transmitter transmitting a time standard signal independently of the communication standard to the first clock and setting the first clock in response to the time standard signal.

Abstract: A method of terminating two or more constituent encoders of a turbo encoder employing a turbo code, comprising the step of: generating tail input bits at each of two or more constituent encoders, including deriving the tail input bits from each of the two or more constituent encoders separately from a contents of shift registers within each of the two or more constituent encoders, after an encoding of information bits by the two or more constituent encoders; puncturing one or more tail output bits such that 1/R output tail bits are transmitted for each of a plurality of trellis branches, wherein R is a turbo code rate employed by the turbo encoder during an information bit transmission. In yet another variation, the step of puncturing the tail output bits further comprises the step of: transmitting, during trellis termination, the tail output bits, only if they are sent from an output branch of one of the two or more constituent encoders that are used during information bit transmission.

Abstract: A method and apparatus for an adapter card, for use in a computer, to provide conditional access by the computer to incoming data streams while maintaining the security of information by maintaining a listing of addresses corresponding to data streams which the computer is authorized to receive, receiving and determining the address of a frame, determining whether the frame address matches an address maintained in an Access Table, and processing and transmitting only those frames of data streams which the computer is authorized to receive.

Abstract: A coordinatable system of geosynchronous (24-hour), inclined, and slightly elliptical satellite orbits enables spectrum re-use by forming “highways” of moving “slots” in the latitudes above and below the geostationary (GSO) belt worldwide. Each of a plurality of repeating ground tracks is shared by multiple satellite orbits (and thus slots). These are phased to achieve minimum specified angular separation from other slots using the same frequencies. Ground track (and thus orbital) parameters are chosen to realize specified shapes and are located at specified longitudes of symmetry to maximize the total number of slots. Consideration is given to specified constraints on service area coverage, elevation angle, and time coverage.

Abstract: A system of inclined geosynchronous satellite orbits has a service area defined on a surface of the earth. The service area has elevation angles greater than a predetermined minimum elevation angle elevation angle from the horizon. A satellite has an orbit with respect to the earth having a sky track when viewed from within said service area. An operating arc is defined by a subset of points on the sky track within the service area. The satellites operate consecutively on the operating arc.

Abstract: A system and method for free space optical communication include at least one reconfigurable terminal (30) using dual-wavelength operation for isolation between transmitted and received signals in combination with polarization switching to separate and steer the transmitted and received signals to and from corresponding transmitters (40) and receivers (48). The polarization based switching provides wavelength independent beam steering to facilitate interchanging of wavelengths for transmitted and received signals. A controllable or passive polarization changer (56) such as a wave plate or polarization rotator allows the communication terminal (30) to be reconfigured without also requiring the repositioning and associated precision alignment of beam steering optics (54, 62, 66).

Abstract: A satellite-based communications system operating at high data rates includes a plurality of communications satellites each having an uplink and a downlink antenna for receiving and transmitting a plurality of spot beams corresponding to a plurality of coverage areas at a plurality of frequencies. The system further includes a plurality of dedicated communications links between a source location in one of the plurality of coverage areas and a destination location in another one of the plurality of coverage areas wherein the plurality of dedicated communications links are each assigned an exclusive time interval for transmitting and receiving communications signals to and from each of the plurality of satellites. The plurality of satellites each have an uplink and downlink antenna beam switch coupled to the uplink and downlink antennas for selecting a reconfigurable subset of the plurality of spot beams based on the time interval.

Abstract: A system and method for distributing high definition television (HDTV) and standard definition television (SDTV) signals via satellite is disclosed. At the transmission station an MPEG-2 video encoder compresses a video signal and a digital encoder encodes an audio signal. The compressed video and the encoded audio are coupled to PES packetizers, which generate video and audio packetized elementary data streams having PES headers and PES payloads. Within each PES header is a presentation time stamp (PTS), which is representative of the time at which the payload is to be displayed to the user. The packetized elementary data streams are multiplexed together by a transport multiplexer and repacketizer and broadcast to receiver stations, via satellite. The receiver stations receive the PES information and obtain the PTS. A receiver station multiplies the PTS by 300 and compares its local clock reference to that time.

Abstract: A torque motor includes an annular, cylindrically symmetric, stationary inner support ring having an outer surface, and a plurality of inner permanent magnets affixed to the outer surface of the inner support ring. The torque motor further includes an annular, cylindrically symmetric, stationary outer support ring overlying the inner support ring and having an inner surface, and a plurality of outer permanent magnets affixed to the inner surface of the outer support ring. There is an annular, cylindrically symmetric, rotationally movable rotor body ring lying between the inner support ring and the outer support ring, wherein the movable rotor body ring has a plurality of openings therethrough. A plurality of electromagnet rotor coils is supported in the openings on the movable rotor body ring.

Abstract: A requesting terminal includes an interface that allows a user to select whether data downloaded from a network (such as the Internet) is transmitted to the requesting terminal via a high-speed link, such as a satellite link, or a lower speed link, such as a terrestrial link. Preferably, the terrestrial link (which may comprise a conventional dial-up Internet connection) is a two-way link, wherein the requesting terminal transmits data requests to the network via the terrestrial link. The data requests generated by the requesting terminal are modified to designate whether the requested data should be downloaded from the network via the terrestrial link or the satellite link. The terrestrial link may also be automatically selected for certain applications.

Abstract: In a satellite communication system (20), a method (50) and system of locating terrestrial-based user terminals (UTs). A UT (23) is located by a two-tier estimation procedure. Under this procedure, an initial estimate of the UT location is performed based on absolute signal propagation delay and Doppler shift measured from a communication link between a satellite and the UT. A second, refined estimate of the UT location is then performed based on the results of the initial estimate. The second estimate can be a function of the absolute propagation delay and absolute Doppler, as well as differential delay and differential Doppler measured from transmissions from two or more satellites (21-22) to the UT (23).

Abstract: A semiconductor passivation technique uses a plasma enhanced chemical vapor deposition (PECVD) process to produce a silicon-rich nitride film as a passivation layer on a Group III-V semiconductor device. The silicon-rich film has a nitrogen to silicon ratio of about 0.7, has a relatively high index of refraction of, for example, approximately 2.4, is compressively stressed, and is very low in hydrogen and oxygen content.

Abstract: An integrated circuit for processing a speech signal in accordance with a CELP standard includes a plurality of processing elements coupled to a data bus in parallel. Each processing element includes a multiplier and an accumulator. The integrated circuit further includes an auxiliary processing element, which is also coupled to the data bus and has a division unit and a comparator. The plurality of processing elements and the auxiliary processing element are also coupled in a pipeline formation.

Abstract: A method and system for determining a position of an orbiting transceiver in a communications network includes at least a first and second transceiver at a first and second known location, respectively, on Earth. The first and second transceivers are adapted to transmit and receive communications signals to and from the orbiting transceiver. A processor coupled to one of the first and second transceivers determines a first and second range measurement between each of the first and second transceivers and the orbiting transceiver, respectively, as well as corresponding first and second range rates representative of a time rate of change of the first and second range measurements.

Abstract: A mobile satellite (MSAT) system is provided for establishing a single-hop terminal-to-terminal call between two terminals. The MSAT system maintains a signaling path between each terminal and a gateway station during the terminal-to-terminal call although a call path between the mobile switching center and the originating terminal is blocked by the satellite. During single-hop call establishment, satellite channels for the terminal-to-terminal call path and for signaling are allocated. The allocated channels are assigned when a direct satellite link for the terminal-to-terminal call is established; otherwise, the call can proceed as a double-hop call using previously assigned satellite channels. A verification signal is sent on the direct satellite link which is for processing by the terminals and which contains information that causes the signal to be ignored by a gateway station.

Abstract: A method of broadcasting controlling data streams and remote receiving apparatus for using the same are disclosed. A viewer-channel-to-broadcast channel (VCBC) map is employed to map one or more controlling data streams to one or more channels. The VCBC map is stored in memory. When a user tunes to a channel, the VCBC map is checked to determine if a controlling data stream is associated with the tuned channel. The VCBC map is periodically updated and broadcasted.

Abstract: A method and device is described herein for displaying a television picture comprised of several standard aspect ratio images on widescreen and standard aspect ratio video monitors. A widescreen image including several smaller aspect ratio images are assembled and broadcast. A receiver with a widescreen monitor display can display the entire widescreen image. A receiver with a conventional aspect ratio monitor display can display a combination of the smaller aspect ratio images. The device includes a frame store for storing image information, image configuration logic for determining a configuration of image information, and frame address logic to write image information to frame store with a configuration according to image configuration logic.

Abstract: A novel organic light-emitting pixel structure provides improved contrast pixels suitable for use in high-contrast passive- and active-matrix displays. A dark, low-reflectance film is placed on a reflective or transparent substrate, which acts to absorb and/or trap ambient light impinging on the pixel and improving its contrast between on and off states. Optical scattering is reduced by fabricating a vertical wall around each pixel which effectively blocks out light emitted from adjacent pixels, and prevents the scattering of the pixel's own emitted light. Light is emitted through a transparent upper electrode, which allows the substrate to be non-transparent. An active-matrix display is thus built on a single silicon substrate, with the crystalline silicon transistors needed to drive the active-matrix fabricated alongside their respective pixels, and with the walls surrounding the pixels formed from the drive circuitry itself.

Abstract: A system (20) and method (40) for determining a user terminal (23) location on the surface of the earth relies on the signal propagation delay and Doppler shift of radio frequency (RF) transmissions between the user terminal (UT) (23) and a satellite (22). An iterative procedure is employed to improve the accuracy of the location determination. Within the procedure, the position of the UT is estimated based on the propagation delay, Doppler shift, and a spherical approximation of the earth's shape. The radius of the earth at the estimated UT position is adjusted using a predetermined model of the earth's shape, such as an ellipsoid approximation. The adjusted radius value is then used to re-estimate the UT location using the spherical approximation. The iterative procedure continues until the estimated UT location converges to a predetermined accuracy.

Abstract: A redundant system, such as a redundant-modem system, having a plurality of similar components capable of operating independently of each other. At least one of the components serves as a spare component. The system further includes a plurality of switches connected to the inputs and outputs of the components such that the inputs and outputs of each of the components may be rerouted through the component operating as the spare. When operating as a spare, a component monitors status information received from the other components and detects when one of the other components has failed. When one of the components has failed, the component acting as a spare controls the switches such that the spare component (20b) replaces the failed component.