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: An apparatus for generating a modulated signal which includes a modulator operative for receiving a first signal and input data signals, and modulating the first signal in accordance with the input data signals so as to produce a modulated reference signal; a first frequency divider coupled to the modulator output, operative to reduce the frequency of the modulated reference signal by a predetermined factor; a signal generator operative to produce a second signal; a first mixer having a first input coupled to an output of the first frequency divider and a second input coupled to the output of the signal generator. The first mixer operates to frequency translate the modulated reference signal by an amount equal to the frequency of the second signal. In addition, the signal generator of the present invention contains a direct digital synthesizer coupled to a second phase lock loop which operates to up-convert the output signal of the DDS to the microwave region.

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: A traveling wave tube incorporates a collector having a plurality of collector electrodes, one or more of which is operated at a potential below that of the cathode so as to collect electrons having associated energies greater than the cathode potential (E.sub.K), and thereby act as a high impedance current source. The current from the collector electrode operated below the cathode potential (E.sub.K) is converted by a power converter to an alternating current signal that can be either magnetically coupled to the high voltage transformer (T.sub.1) of the traveling wave tube power supply, or coupled to an external load with a transformer (T.sub.2), thereby improving the operating efficiency of the traveling wave tube system.

Abstract: Various structures for cantilever beam tunneling rate gyro devices formed on a single substrate are disclosed. A cantilever electrode having a plurality of portions extending from the substrate with one end of the cantilever is suspended above the substrate at a distance from a tunneling electrode so that a tunneling current flows through the cantilever and tunneling electrode in response to an applied bias voltage. The cantilever and tunneling electrodes form a circuit that produces an output signal. A force applied to the sensor urges the cantilever electrode to deflect relative to the tunneling electrode to modulate the output signal. The output signal is a control voltage that is applied between the cantilever electrode and a control electrode to maintain a constant tunneling current. In the preferred embodiment, two cantilever portions extend from the wafer surface forming a Y-shape. In a further embodiment, a strap is fabricated on the cantilever electrode.

Abstract: A method of preparing Li.sub.x Mn.sub.2 O.sub.4 for a secondary battery includes mixing lithium nitrate, magnanese nitrate and citric acid. A complex citrate solution is formed in the substantial absence of a polyhydroxyl alcohol. The complex citrate solution is dehydrated to produce a precursor. The precursor is then heated at a substantially constant rate and then calcined to provide a spinel compound.

Abstract: A remote programmer connectable to a satellite television receiver prompts a user to enter commands representing a satellite or local television program to be recorded by a video tape recorder. The remote programmer issues programming commands to the satellite television receiver and the video tape recorder to cause the program to be provided at the output of the receiver and recorded by the video tape recorder at a specified time.

Abstract: A method and apparatus are disclosed for controlling the operation of a synchronous rectifier used in power conversion circuitry. The disclosed method and apparatus senses the voltage across the synchronous rectifier, and turns the synchronous rectifier OFF when the voltage across the rectifier is about to change direction. Preferably, the synchronous rectifier is commanded OFF at the approximate instant when the voltage across the rectifier reaches approximately zero, which also corresponds to a current of approximately zero. Accordingly, currents are prevented from flowing in the reverse direction in the synchronous rectifier. This results in approximately zero voltage and zero current switching when the rectifier is turned OFF, thereby minimizing switching losses.

Abstract: An message handling system for handling the delivery of critical and time critical messages for a near-real-time or real-time simulation environment. A message delivery type (38) accompanies each message (34) to designate whether the message (34) is delivery critical (46) or time critical (42). A message receiver (50) receives the message (34). A message delivery selector (58) selects a protocol based on the message delivery type (38) as determined by a message type determinator (54). The selected protocol conforms to a message format which has a common header and a message component. The message (34) is then sent to the intended recipient computer via the selected protocol.

Abstract: A video broadcast system is provided with an apparatus for processing a plurality of program signals corresponding to, for example, movies or other prerecorded programs, to selectively reduce the bandwidth required to transmit or broadcast the program signals. The signal processing apparatus includes a rate controller for generating a rate reduction factor based upon the data rates of the first and second program signals, a first channel processor coupled to receive the first program signal, and a second channel processor coupled to receive the second program signal. Each of the channel processors includes a data path for selectively reducing the bit rate of the program signals based upon the rate reduction factor.

Abstract: A method and apparatus for performing fractional minimum shift key modulation for a very small aperture terminal. A signal with a fractional modulation which appears to be frequency shift key is generated in the indoor unit. The outdoor unit employs a novel multiplication method to translate this signal to a minimum shift key modulated signal for satellite transmission.

Abstract: A collector for collecting an electron beam in a traveling wave tube is disclosed. The collector has an input end for receiving the electron beam from the traveling wave tube. The collector also has a plurality of stages biased at given voltages and arranged along a common collector axis and positioned at a different axial position with respect to the input end. A stage is biased more negatively with a voltage than a successive stage positioned axially farther from the input end to generate an electrostatic focusing lens for focusing the electron beam toward successive stages thereby increasing the collection efficiency of the collector.

Abstract: A statistical multiplexing apparatus for permanently recording a plurality of video signals on a video generator so that video programs represented by the video signals can be repeatedly broadcast is provided with a video analyzer for analyzing a first video signal and a second video signal and generating a first compression signal and a second compression signal, a first video encoder for encoding the first video signal at a variable rate determined by the first compression signal to form a first encoded video signal, a second video encoder for encoding the second video signal at a variable rate determined by the second compression signal to form a second encoded video signal, and a video generator for permanently recording the first and second encoded video signals so that the first and second encoded video signals can be repeatedly broadcast from the video generator.

Abstract: A method and apparatus for transferring data signals with personalization layers for symbolically compressed objects comprises a transmitter having an encoder and a receiver having a decoder. The encoder includes a segment selector for identifying signal segments from a group of speech, audio, video, and graphic signals, each segment comprising a representation of a physical waveform. The encoder includes a plurality of encoder libraries, one of the libraries containing the representation of a generic waveform and a symbolic code for the generic object. The decoder has a second plurality of libraries corresponding to the plurality of encoder libraries, and contain the generic waveform, the symbolic code corresponding to the generic physical waveform, and the difference information quantity as a personalization layer of data representing the difference between the generic object code and the waveform from which the generic object was extracted.

Abstract: An apparatus for statistically multiplexing a plurality of video signals is provided with first and second complexity detectors which generate first and second complexity signals which relate to the complexity of first and second video signals, respectively, and first and second encoders for compressing the first and second video signals at variable compression rates to generate a first and second compressed video signals. The apparatus also includes a controller for controlling the variable compression rates of the encoders based on the complexity signal signals and a multiplexer coupled to receive the compressed video signals. The apparatus may be provided in a broadcasting system, such as a satellite is broadcasting system.

Abstract: A rocket engine is prepared by fabricating a combustion chamber having an annular wall as a single piece of material. The wall has a first axial region with a first inner diameter, a second axial region with a second inner diameter greater than the first inner diameter, and an inner wall step transition between the first axial region and the second axial region. The wall is formed by furnishing an oversize blank of the wall material and electrical discharge machining or grinding it to the final size. The combustion chamber is attached to an injector by bonding an annular metallic deposit to the first axial region of the combustion chamber, providing an annular adaptor ring, first welding the adaptor ring to the metallic deposit, and second welding the adaptor ring to the injector.

Abstract: A method is provided for preparing the surface of a cyanate ester resin composite for metal plating. More particularly, a layer consisting essentially of cyanate ester resin is applied to the surface of the composite. Thereafter, the surface of the resin layer is etched, preferably by treatment with an etching solution containing either a quaternary ammonium hydroxide or a primary amine. Upon completion of the etching process, the cyanate ester resin layer may be successfully plated with metal. The method of the invention operates to improve adhesion between the cyanate ester resin composite and a subsequently-plated metal by providing the composite with a homogenous distribution of mechanical anchoring sites for a subsequently-plated metal, such that uniformity of adhesion is achieved.

Abstract: A method and apparatus for allocating shared communication channels between a voice transceiver segment and a data/CDPD transceiver segment of a cellular radio communication system incorporating a CDPD overlay. A LAN provides a communication path for transmitting channel allocation messages directly between the voice transceiver segment and the data/CDPD transceiver segment. The channel allocation messages function to distribute shared channels according to a predetermined protocol that includes a priority to either the voice or data/CDPD segment.

Abstract: In a predictive manner, bandwidth requirements for each pre-compressed information frame are sent to a concentrator so that the pre-compressed information and other information is efficiently concentrated without cropping any information. Specifically, the bandwidth requirement for each one of multiple data frames is obtained and stored with the information data frames. The multiple data frames are concentrated with additional data into one data stream, and concentration is controlled with the aggregate bandwidth requirement of the bandwidth requirements for each one of the multiple data frames. A processor with an information data input, a processed data output and a rate data output for each frame of the processed data output is coupled to a storage device. A concentrator operatively connects to the storage device. The concentrator is capable of receiving at least a first and second frame of information data and has a concentrated output.

Abstract: Spin-stabilized spacecraft are provided which facilitate simple attitude maneuvers and the use of high-gain antennas and efficient solar panels without the need for complex control systems and an excessive number of thrusters. They include a rotor and first and second spacecraft platforms wherein the rotor and the first and second spacecraft platforms are rotatably coupled together and a spin thruster system is arranged to urge and maintain the rotor in a spacecraft-stabilizing spin about the rotor axis. A first rotary-drive mechanism couples the first spacecraft platform to the rotor and a second rotary-drive mechanism couples the second spacecraft platform to the first spacecraft platform. An attitude thruster is spaced from the rotor axis and oriented to generate an axial thrust component in the rotor for synchronous control of the inertial attitude of the rotor axis.