Abstract: A method and apparatus for searching a program guide comprising program information for a plurality of different program sources. The program information includes the titles of the programs, the channel on which each program is to be shown, and the time at which each program is to be shown. The viewer first enters the title of a desired program. The program guide is then reviewed so as to identify each occurrence of the title of the desired program. If the desired program is contained in the guide, the time and channel associated with each identified occurrence of the program is displayed.

Abstract: A method, and related apparatus, for coherently demodulating phase-modulated data which is coherently transmitted (i.e., without the use of differential encoding of the data) on Rician fading channels. The method uses phase unwrapping and phase interpolation, in conjunction with block phase estimation, to achieve a performance comparable with coherent detection of coherently transmitted data while reducing processing requirements.

Abstract: A multiband millimeterwave antenna system for communicating signals in multiple frequency bands is disclosed. A main antenna body is connected to antenna extensions by micro-electro-mechanical switches. By opening and closing the switches, the length of the antenna can be altered. The antenna is coupled to a microstrip feed line by an aperture. A series of matching stubs match the impedance of the feed line for the various signal frequencies.

Abstract: An electronic mail alert system includes an e-mail server for administering an e-mail account of an e-mail service subscriber and an e-mail alert front-end. The e-mail server includes a subscriber account memory for storing an indication that e-mail has been received by the e-mail server for an e-mail alert service subscriber as well as a communication port for allowing the e-mail alert service subscriber to retrieve e-mail from the e-mail server via a subscriber terminal remote from the e-mail server. The e-mail alert front-end is coupled to the e-mail server and polls the e-mail server periodically to determine whether e-mail for the e-mail alert service subscriber has been received by the e-mail server.

Abstract: A method for displaying a video sequence depicting motion of at least one video object by sequential presentation of a plurality of frames includes storing a low resolution representation of the video object, generating and displaying a first frame of the sequence based on the low resolution representation, updating the low resolution representation, and generating and displaying a subsequent frame of the sequence based on the updated representation. The method may include calculating a quality metric to determine when updating is necessary.

Abstract: An apparatus and method is disclosed, utilizing a communications network (in this particular design, it is a GEM (Geo-Mobile) satellite system) to initialize a Global Positioning System (GPS) receiver (such one integrated into a handheld user terminal, or phone used within the communication network) to enable the GPS receiver to quickly acquire GPS satellite signals and perform positioning calculations. By systematically feeding the GPS receiver key pieces of information (GPS satellite trajectories, time estimate, position estimate, and additional positional references), the time to first fix (TTFF) of the GPS receiver can be drastically reduced.

Abstract: An integrated digital circuit is protected from reverse engineering by fabricating all transistors of like conductivity with a common size and geometric layout, providing a common layout for different logic cells, connecting doped circuit elements of like conductivity with electrically conductive doped implants in the substrate rather than metalized interconnections, and providing non-functional apparent interconnections that are interrupted by non-discernable channel stops so that all cells falsely appear to have a common interconnection scheme. The camouflage is enhanced by providing a uniform pattern of metal leads over the transistor array, with a uniform pattern of heavily doped implant taps from the transistors for connection to the leads; undesired tap-lead connections are blocked by channel stops.

Abstract: A method of damping nutation and removing wobble of a spacecraft provided with first and second momentum sources having linearly independent momentum components in the plane transverse to the given axis. The method includes sensing angular velocities of the spacecraft along orthogonal first and second axes in the transverse plane, and generating velocity signals representative of the angular velocities. The velocity signals are processed to form control signals representative of desired torques for driving the momentum sources. The desired torques have a first additive component proportional to the angular velocities for removing the wobble and a second additive component proportional to the first derivatives of the angular velocities for damping the nutation.

Abstract: An electronically scanned antenna that is manufactured using semiconductor material and device fabrication technology. The antenna has a semiconductor substrate having a plurality of stubs projecting from one surface. The semiconductor substrate may be silicon, gallium arsenide, or indium phosphide, for example. A first conductive layer formed on the surfaces of the semiconductor substrate and along sides of the stubs so that the stubs are open at their terminus. The conductive layers form a parallel plate waveguide region. A diode array having a plurality of diode elements is formed in the semiconductor substrate that are disposed transversely across the semiconductor substrate and longitudinally down the semiconductor substrate between selected ones of the plurality of stubs. The diode array may comprise an array of Schottky or varactor diodes, for example.

Abstract: A communication system and a method of providing a feeder link to an earth orbiting satellite transponder having a mobile link illuminating spot beams with associated access channels, control channels and traffic channels for multiple user terminals (UTs) using the satellite transponder as the reference point to correct for dynamic frequency errors including the Doppler in the feeder link and in the mobile link caused by the satellite motion and the satellite translation error. A satellite access node (SAN) includes one or several radio frequency terminals (RFTs) and a satellite basestation subsystem (SBS). The RFT performs the center Doppler correction for each of the channels of the feeder link to the satellite transponder. The SBS corrects the feeder link residual Doppler and the satellite translation error for each channel and calculates the Doppler in the mobile link between the satellite transponder and the median Doppler line of each spot beam on the earth or each UT.

Abstract: The inner surface of a barrel for a traveling wave tube is formed with a set of tracks extending parallel to the longitudinal axis of the barrel. The rods supporting the traveling wave tube circuit assembly are supported in the tracks. The tracks are formed by forcing a tool having track-forming elements through the barrel, or a succession of ever-larger tools may be used to first form and then gradually enlarge the tracks.

Abstract: Apparatus compensating for gain variations versus frequency of a traveling wave tube (TWT) is disclosed. The apparatus provides an RF interaction circuit section designed with specified mismatches causing internal reflections of the RF waves, such that the overall gain response is flattened out or inverted.

Abstract: A swept frequency communication system includes a modulator that multiplies a frequency sweep signal with one or more underlying modulated communication signals to produce a swept frequency signal having a number of headerless tracks located directly adjacent one another in the swept frequency/time domain. A demodulator receives the swept frequency signal after that signal has been passed through a wireless channel, isolates a particular track of the received swept frequency signal to prevent a near/far problem, A/D converts the isolated track, resweeps the digitized isolated track, and then equalizes the isolated track using a blind channel equalizer to eliminate time-varying amplitude/phase impairments caused by transmission of that track through the wireless channel. The demodulator then removes the sweep signal from the equalized swept frequency track and decodes or demodulates the underlying modulated communication signal.

Abstract: An approach for connection of an antenna employs an antenna including at least one antenna contact; a swivel collar slidably coupleable with the antenna and including at least one collar contact; and an antenna coupler/connector insertable into the swivel collar. The approach may also be characterized as involving moving an antenna by sliding the antenna within a swivel collar, moving an antenna contact at an end of the antenna away from a swivel contact in the swivel collar; and inserting an antenna coupler/connector into the swivel collar including contacting the collar contact with a contact pad on the antenna coupler/connector.

Abstract: A telemetry system for receiving data from large arrays of sensors, in which the sensors are located in an unprotected environment, is implemented using fiber optic components. Laser sources, located in a protected environment, transmit light through the boundary separating the protected environment from the unprotected one. The light is then split into a number of beams and fed to electro-optical modulators, where it is modulated in response to electrical signals received from the sensors. The modulated light signals are then wavelength-division multiplexed and transmitted back through the environment boundary, where they are amplified, demultiplexed and converted to electrical signals. Multiplexing reduces the number of boundary penetrations, and the use of highly stable electro-optical modulators eliminates the need for signal conditioning electronics at each sensor.

Abstract: A reconfigurable filter system designed using micro-elecro-mechanical (MEM) switches is disclosed. The filter comprises a transmission line with one or more filter stubs coupled to the transmission line by MEM switches. The impedance of the filter system is altered by selectively opening and closing the MEM switches, which alters the filter characteristics of the filter system. Alternatively, the characteristics of the filter system are altered by using the MEM switches to selectively alter the length of filter stubs attached to the transmission line.

Abstract: Spacecraft stationkeeping and momentum-dumping methods are facilitated by the use of selected diagonal pairs of thrusters which are positioned adjacent to nadir or antinadir spacecraft faces. The methods maintain an elliptical Sun-synchronous orbit, counter triaxiality forces and facilitate momentum-dumping of momentum and/or reaction wheels. They are particularly suited for inclined orbits.

Abstract: A video image indexing system includes a method for identifying categories in compressed digital data for improved retrieval of video images. An encoder receives a frame and digitizes the image data while a sub-band coder codes each digitized frame at a plurality of transform levels to derive categorized data segments. Data segments are stored and then retrieved according to minimum entropy of Eigenvalues in a first transform level. Preferably, the compression is improved by creating a residual image of each frame by subtracting a predicted frame image from the actual frame image. This compression of data enhances the recreation of lossless video images at the receiver.

Abstract: A microelectromechanical (MEM) device includes a substrate and a flexible cantilever beam. The substrate has positioned thereon a first interconnection line separated by a first gap and a second interconnection line separated by a second gap parallel to the first interconnection line. The substrate also has positioned thereon a first and second primary control electrode wherein one of the first and second primary control electrodes is positioned on one side of one of the first and second interconnection lines and the other one is positioned on the other side of the other first and second interconnection lines. The flexible cantilever beam has a top surface and a bottom surface and a beam width slightly larger than the gap widths at the gaps. A flexible anchor is secured to the bottom surface of the beam at a center of the beam and attached to a center of the substrate so as to position the beam orthogonally to the first and second interconnection lines.

Abstract: The method and apparatus for determining group delay of a satellite communications channel includes a low frequency vector network analyzer and microwave swept synthesizer which together generate modulated signals. A sample of the signals transmitted to a satellite and the signals retransmitted from the satellite are compared in the network analyzer to obtain the phase of the signals. The phase of a reference signal is measured prior to and after each test frequency of the communications channel. A quasi-real time phase reference can be obtained by interpolation. Thus, the reference phase due to movement of the satellite with respect to the earth station during group delay measurement may be removed.