Abstract: An ultra-wideband (UWB) communications system combines the techniques of a transmitted reference (TR) and a multiple access scheme called delay hopping (DH). Combining these two techniques using UWB signaling results in a penalty in signal-to-noise ratio (SNR) over conventional pulse position modulation (PPM) techniques but avoids the synchronization difficulties associated with conventional approaches. The signaling pulse waveforms are designed to insure that their power spectral densities, after any frequency translation to the center of an operating band, are essentially spectrally disjoint with frequencies that must be protected. This TR technique is combined with the DH multiple access technique to create a UWB communications scheme that has a greater multiple access capacity than does the UWB TR technique by itself.

Abstract: A low cost frequency shift keying communications system for communication between utility meters within a local area network and for communication with a central database. Transmitters coupled to the utility meters transmit utility meter data measurements over power lines to at least one power line receiver associated with another utility meter within the local area network. The power line receiver communicates the data measurements from each utility meter to the central database via telephone or radio frequency transmitter.

Abstract: In a system for optimizing television reception by a television receiver receiving a diversity of input signals from a plurality of antennas, one of a plurality of combiners and television tuners selects the strongest combination of input signals for viewing and another scans the various combinations of input signals searching for a combination significantly stronger than the combination being viewed. A plurality of multiplexers selects the output signal of one combiner and transmits the selected signal to one of the tuners. A signal evaluation module evaluates the strength of the combinations of input signals and compares the strength of each combination of input signals to the strength of the viewing signal, looking for a superior signal. A control processor controls the combination of input signals selected by the combiners and the combiner output signal selected by the multiplexers.

Abstract: An Advanced Television Standards Committee (ATSC)-compliant pilot tone is generated within an 8-VSB (eight level vestigial sideband) transmission in order to enable Quadrature Amplitude Modulation (QAM) receiver designs to more efficiently process the transmitted/received 8-VSB signal. The method and apparatus also efficiently removes the pilot tone before using conventional QAM demodulator equipment for directly demodulating the 8-VSB signal.

Abstract: Reduction in the time required for an Advanced Television Standards Committee (ATSC) digital television tuner to equalize, converge, and acquire a digital television signal suitable for viewing, wherein early model ATSC tuners also include a National Television Standards Committee (NTSC) analog tuner, is achieved by using a microprocessor to control use of the NTSC tuner to scan television channels. A channel measurement module converts the scanned analog signal to a digital signal, and the equalization coefficients for the resultant digital signal are stored in memory. The equalization coefficients stored in memory are then accessed and utilized to tune in new channels on the ATSC tuner. The amount of time necessary for the ATSC tuner to tune in a new channel is thus reduced. When the ATSC tuner is in use, the equalization coefficient data stored in memory are periodically updated.

Abstract: An Internet download enhancement system for downloading a file comprising an application arranged to initiate a download process and receive a downloaded file over one of a narrow band download path and a broadband broadcast download path, wherein modules in communication with the application are arranged to provide selectable download options among the available download paths. The selectable download options are based at least on an unused bandwidth of one or more of the download paths, thereby enabling the input of a selected download option. The modules are arranged in response to the input to cause a download process to download files over one of the narrow band download path and the broadband broadcast download path and then to output the downloaded file to application.

Abstract: An integrated tracking, telemetry and local area networking system is provided. A communications system comprises a broadband subsystem comprising at least one UWB node including a first UWB transceiver and at least one application node linked to the UWB node by a broadband link. The system further comprises a wireless subsystem comprising at least one remote communicator, the remote communicator including a second UWB transceiver. The first and second UWB transceivers are configured to communicate with each other via an UWB communications link.

Abstract: A brevity signaling module for a digital television (DTV) receiver enables the reception of emergency broadcast messages. The overlay signal received at the receiver front end is squared in a squaring loop, producing spectral lines at DC and twice the overlay signal frequency, or 2&ohgr;, where &ohgr;=2&pgr;f and f is the center frequency of the overlay signal. The squared signal is passed through a narrow band filter having a bandwidth sufficient to pass a spectrum containing a plurality of tones 2&ohgr;, 2&ohgr;1, 2&ohgr;2, . . . , 2&ohgr;n, where 2&ohgr;1, 22, . . . , 2&ohgr;n are different frequency tones assigned to different auxiliary functions. The detected tone is used by a control module to determine whether normal multipath processing should be performed or whether this processing should be suppressed and auxiliary functions performed, including turning on the DTV receiver power in order that an emergency broadcast message might be conveyed to persons in the vicinity of the DTV receiver.

Abstract: Training sequences designed for N-VSB systems within the embodiment of an N-squared QAM receiver facilitate designing 8-VSB receivers using methodologies of 64-QAM receiver design. A receiver designed using such methodologies converts the received modulation into a signal which can be accepted by circuitry for decoding 64 level quadrature-amplitude modulation (64-QAM) signals. This process provides a better signal to noise ratio reception than the conventional I-channel only decoding circuitry of most 8-VSB receivers. This process also employs training and equalizing algorithms developed for 64-QAM receivers which are superior to equivalent algorithms for 8-VSB receivers. The invention can be generalized to N-VSB conversion into M-QAM where M=N2. Adaptive equalization algorithms for 8-VSB transmissions implemented within the context of the 64 QAM receiver are superior to present single-channel VSP processing receivers.

Abstract: DTV broadcast transmission is provided with a ultra wideband overlay signal which is used by suitably equipped DTV receivers to dynamically estimate the channel and allow expeditious and effective mitigation of changing multipath conditions. Periodic correlation peaks are detected in the received overlay signal, and the timing and magnitude of other peaks in the received overlay signal are used to mitigate multipath in the received signal. A DTV receiver that is not equipped to process the overlay transmission will not be significantly affected by the overlay signal.

Abstract: An antenna comprising two essentially identical electrically conducting rectangular plates lying in parallel planes and separated so that a gap is formed between the plates also includes a dielectric situated within the gap and exhibiting a relative permittivity that changes with frequency. Electrical connectors connect the plates to corresponding conductors that carry the signal to be radiated by the antenna.

Abstract: A receiver for enabling one-way communications in a GHM network which does not interfere with or reduce the capability of the GHM network. The receiver detects a small modulation factor signal present on the GHM signal normally transmitted by the GHM transmitter. If the frequency of the modulated signal corresponds to a pre-defined frequency, then the receiver generates a command signal to, for example, a relay, annunciator, or other external device. More particularly, and in one embodiment, the receiver includes a filter which partially isolates the GHM energy from the lower 60 Hz harmonics. The receiver also includes a envelope detector coupled to filter. The envelope detector is coupled to a frequency detector. The frequency detector is coupled to a command decoder. The command decoder determines whether a plurality of AM modulation frequencies are present on the received signal.

Abstract: A digital television (DTV) receiver is provided with a sounder comprising a wideband transmitter and a plurality of wideband receivers having separately located receiving antennas, so that the sounder is, in effect, a bistatic radar system for any given channel, in order to characterize a significant nearby, indoor reflector. A microprocessor receives the timing information generated by the wideband transmitter impulses and the reflected impulse returns to each of the receiving antennas, and calculates a multipath model representing the three-dimensional location of a significant, nearby scatterer.

Abstract: The existing ATSC broadcast standard is modified to improve both the speed at which the periodically transmitted training sequence is found after channel selection by a viewer and the speed at which synchronization is achieved to a continuous wideband overlay signal used for equalization of the decoded signal. The modification involves slight amplitude modulation of the pilot signal in a manner synchronized with the transmission of the training sequences. The modulation of the pilot signal is sufficiently small to be ignored by existing ATSC receivers; that is, it is backwards compatible. Properly equipped receivers can detect, more quickly than receivers not so equipped, transmission of the training sequence by decoding this pilot signal modulation, thereby being capable of providing a decoded image to a viewer more quickly after a channel change than a receiver not so equipped.

Abstract: An N-VSB (vestigial sideband) modulation signal is converted into an M-QAM (quadrature amplitude modulation) signal, where M=N2, by shifting the symbol rate frequency of a received N-VSB modulation signal to center the waveform spectrum about zero Hertz prior to complex demodulation so that data symbols will alternately appear on demodulated I and Q channels. A pilot tone of the received N-VSB modulation signal is removed to eliminate any bias in the both I and Q channels. Symbol timing between I and Q channels is offset, and quadrature amplitude demodulation of the I and Q channel signals generate alternating I and Q channel data symbols. Alternating inversion of the alternating I and Q channel data symbols recovers the N-VSB symbol data.

Abstract: An electromagnetic system for detecting cracked rail and enhancing traction when necessary, includes wiring coils around wheel axles, and a corresponding power source for supplying power to the coils for producing electromagnetic flux. The produced electromagnetic flux is routed through the wheel axles, wheels and rails in a closed circuit. When a cracked rail is encountered along the route, the circuit will be interrupted or open, resulting in a changed flux pattern. This pattern change is detected by a flux sensor, and the geographic location of the crack in the rail is determined. The electromagnetic system further includes an electromagnetic wheel loading means for generating an attraction to the rails. The generated attraction to the rails increases friction between the wheels and the rails, thereby increasing traction to enable hauling greater loads up steep grades.

Abstract: A low cost and easy to assemble communicating utility meter provides selectable measurement, calibration, display, and communications means so as to be re-configurable based on several factors including; harmonic content of the power signal measured, LCD display alternatives, time of use measurements, bandpass filter settings, power quality measurements, PLC communications alternatives, radio frequency communications alternatives, optical communications alternatives, and hard wire communications alternatives.

Abstract: A linking process allows a head-end unit (HEU) of a railroad train to determine the sequence of cars in the train using wireless links between nodes on the cars, and requires no physical connection between the nodes or cars. Each car in the train is equipped with a wireless communication device which models an oscillator i. Each oscillator is phase-variable, the phase .theta..sub.i linearly increasing from 0 to 1 such that, when the i.sup.th oscillator "fires", transmitting a packet, and phase .theta..sub.i then jumps back to zero. When a car receives the transmission of another car, it changes the phase of its oscillator according to a phase-response curve function, setting up a wave pattern of transmission from nodes, from one end of the train to the other end. The wave pattern, along with protocol logic, enables each car to determine the sequence in which cars are arranged in its vicinity.

Abstract: A communication method reduces both the asset energy requirements and communication channel occupancy in a reduced order GPS asset tracking system. The asset is provided with an indication of its position so as to allow detection of substantial movement of the asset at the asset. Reduced order GPS data derived at the asset, such as a railcar, is compressed to allow for shorter railcar data transmission times. This, in turn, reduces both the transmitter energy requirements and communication-channel occupancy, while allowing substantial railcar position changes to be conveniently detected at the railcar. This capability can be used to save further substantial railcar energy by, for example, reporting to the central station less frequently when the railcar position is unchanging.

Abstract: A system for spread spectrum power line communications employs a harmonic modulation (HM) transmitter coupled to the power line for transmitting message bits to an HM receiver. The spread spectrum accommodates a plurality of HM transmitters simultaneously occupying the same bandwidth. The spectrum of HM, in a frequency range above 60 Hz but below the maximum frequency that will carry through a distribution transformer, is ideal in combating carrier synchronous noise since it can be interleaved with the noise harmonics and therefore be effectively spectrally disjoint with the synchronous noise process spectrum.