Abstract: A service channel is provided for concurrent communication with an amplitude modulated compatible digital broadcast signal. A transmitter receives input program information and input data service and combines the program information and data service to produce composite data. The transmitter generates an over-the-air signal waveform using the composite data. This signal is an amplitude modulated compatible digital broadcast signal. At least one receiver is used in the system to detect the over-the-air signal waveform produced by the transmitter. The receiver parses the composite data into program information and data service. The parsing of this composite data is achieved by using header information provided on each of the input program information and input data service.

Abstract: An improved satellite beam acquisition and crossover technique for finding an appropriate satellite beam by searching for and acquiring a strongest pilot channel, searching for signalling channels on the acquired strongest pilot channel and monitoring the acquired signalling channel. Beam acquisition of a continuous wave pilot as in the preferred embodiment is faster and more reliable than beam acquisition of a modulated channel. Moreover, the acquired pilot channel can be used to unambiguously precalibrate the frequency reference of the mobile terminal. Also, acquisition of the pilot ensures that the corresponding satellite beam is not blocked or shadowed immediately prior to searching for a signalling channel, which significantly improves the reliability while reducing the time required for the search process. Mitigation of fading and shadowing is provided by using fast attack, slow decay non-linear filtering.

Abstract: The carrier tracking loop technique and apparatus provides smooth, accurate frequency tracking, fast reacquisition and doppler tracking over a wide dynamic range. The loop parameters of the carrier tracking loop are varied as a function of mode, i.e. flywheel, tracking or reacquisition modes. The various modes of operation are automatically detected and loop operation is enhanced by non-linear techniques. The enhancements include fourth power sample normalization to improve performance over a large dynamic range and to ease fixed point scaling. A slope limiter is included which aids in coherent detection by reducing phase noise introduced by the carrier tracking loop. Also, a predifferentiation filter further aids in coherent detection by reducing phase noise.

Abstract: A main electrical lead of an electrical generator has an electrical conductor or main lead bushing which transmits electrical current produced by the generator to electrical loads external to the generator. The electrical conductor and the main electrical lead are electrically connected by a mechanical connector and a spring mechanism. The spring mechanism provides a force on the mechanical connector to maintain the conductor and the main lead in sufficient electrical contact so that they can transmit the requisite electrical current. A method of installing the spring mechanism is also provided and includes removing the electrical conductor from the main electrical lead and installing the spring mechanism under pressure betweeen the conductor and the main lead. The electrical conductor is then again mechanically connected to the main electrical lead.

Abstract: A nonsquinting end-fed quadrifilar helical antenna is provided. Each conductor of the antenna is fed with a successively delayed phase representation of the input signal to optimize transmission characteristics. Each of the conductors is separated into a number Z of discrete conductor portions by Z-1 capacitive discontinuities. The addition of the capacitive discontinuities results in the formation of an antenna array. The end result of the antenna array is a quadrifilar helical antenna which is nonsquinting (radiates in a given direction independently of frequency).

Abstract: The inter-disk cavity between turbine rotor disks is used to pressurize cooling air. A plurality of ridges extend radially outwardly over the face of the rotor disks. When the rotor disks are rotated, the ridges cause the inter-disk cavity to compress air coolant flowing through the inter-disk cavity en route to the rotor blades. The ridges eliminate the need for an external compressor to pressurize the air coolant.

Abstract: An apparatus and method are disclosed for controlling the power flow in an electric transmission system including at least two transmission lines, each transmission line having two ends and carrying alternating current at a selected transmission line voltage and fundamental frequency between the ends. At least two alternating voltages at the fundamental frequency of the alternating currents flowing in the transmission lines, with variable magnitude and controllable phase angle relative to the transmission line current, are generated and coupled in series with the transmission lines. The magnitude and phase of each generated voltage are controlled selectively and individually to adjust the effective reactive and real impedance of each transmission line, to control the real power transmitted between the two ends of the transmission line and, concurrently, to control the amount of real power individually transferred between the transmission lines.

Abstract: A method and apparatus are provided for monitoring the operating conditions of an electric generator by producing a signal representative of vibration amplitude in end turns of stator windings of the generator; producing a signal representative of an electrical load under which said generator is operating; comparing the vibration and load signals to store reference data representative of normal or abnormal operating conditions; and producing an output signal based on a comparison of the vibration and load signals with the stored reference data. The output signal is representative of the operational status of the generator.

Abstract: A series compensator for damping power oscillations in an electric power transmission system includes a switching power converter which injects a voltage into the transmission line having a phase angle relative to transmission line current which is controlled to provide reactive compensation and to inject virtual real impedance into the line. The switching power converter is a dc to ac converter which is capable of injecting virtual real impedance into the transmission line by virtue of the fact that it has a power exchange device connected to its dc terminals. Where the power exchange device is a resistor, the switching power converter is capable of absorbing real power during surges in power on the line. Alternatively, the power exchange device is a storage device such as a battery bank or a super conducting magnet, in which case the switching power converter can provide both virtual positive and negative real impedance.

Abstract: A resin-rich electrically conductive felt material is described. The described conductive felt can be used to suppress corona discharge in high voltage generator coils. The conductive felt is prepared by treatment with electrically conducting polymers, such as polyaniline and polypyrrole, and resistivity values ranging from 4,000 to 100,000 ohms may be obtained. This treated felt can be readily impregnated with thermoset resins, such as epoxies, to provide flexible prepregs suitable for coil bonding applications in turbine generators.

Abstract: A bandpass sigma-delta modulator for an analog-to-digital converter is provided in which an RLC circuit connected to the input analog signal is resonant at an intermediate frequency. A Josephson junction connected to the RLC circuit receives the current flowing through the RLC circuit. The Josephson junction emits a voltage pulse which reduces the RLC circuit current when the current in the Josephson junction exceeds its critical current. Selected multiples of the voltage pulse generated by the Josephson junction are fed back to the RLC circuit. A digital output is generated from the voltage pulses generated by the Josephson junction to complete the analog-to-digital conversion of the input signal.

Abstract: A spur-free sigma delta modulator analog-to-digital converter for converting an analog input signal to a digital output signal is provided. A race Josephson junction is provided between the pulse generator and the integrating inductor. The race Josephson junction emits a voltage pulse in response to every sampling pulse. This voltage pulse kills any retained persisting current in the integrating inductor. By adding the race Josephson junction, nonlinearities in the converter are eliminated.A multiple flux quanta feedback generator for creating a multiple digital pulse feedback in response to an input signal is provided. A quantizer connected to the input inductor produces a pulse when the current produced by the input inductor exceeds a predetermined amount. A splitter is connected to the quantizer for producing output pulses. In order to produce 2.sup.n output pulses, 2.sup.n -1 splitters are required. Each of the splitters produces two output pulses in response to a single pulse produced by the quantizer.

Abstract: An improved facsimile machine having at least one edge emitting thin film electroluminescent line array, each array having a plurality of pixels wherein the pixels are selectively activated. A light beam from each pixel is directed to a known point along a line on a document and reflects to a sensor. The reflected beam corresponds to a grey level at the point of reflection on the document and causes the sensor to generate a signal corresponding to that greyness level. Sufficient pixels are provided to generate sufficient light beams to strike all points along a line across a document.

Abstract: The present invention provides an improved active power line conditioner which achieves a significant improvement in peak voltage regulation capability when compared with a similarly-sized device of the prior art. Enhanced peak voltage regulation capability is achieved by reducing the number of turns on the transformer winding connected to the series inverter. As a result, the AC regulation voltage induced across the transformer primary and added to or subtracted from the AC supply voltage will be capable of achieving higher peak levels of short duration. When a reduced-turns-ratio transformer is utilized according to the invention, variations of the AC supply voltage which are within the sinusoidal regulation range of a prior art active power line conditioner having a similarly-sized transformer, the output voltage will remain sinusoidal.

Abstract: An electrical control system includes multiple frames of reference in the error path of a controller. In each such frame, a particular chosen component of the error vector appears as a constant vector and is passed through a pure integrator thus acquiring infinite gain. In the steady state, the net error vector can then be forced to have zero content at each of the targeted frequencies (as set by the rotational velocity of the frames of reference). Both parallel and series configuration of the controller are provided, as well as the control methods used by the controllers.

Abstract: A circuit for producing an output signal representative of the phase angle of a single phase input signal includes a phase shift generator for receiving a single phase input signal and for generating a quadrature signal and a direct signal in response to the single phase input signal, and a phase locked loop coupled to the phase shift generator for generating an output signal in response to the quadrature and direct signals such that the output signal is phase locked with the single phase input signal. A method is also provided for producing an output signal representative of the phase angle of a single phase input signal, comprising the steps of: receiving a single phase input signal; generating a quadrature signal and a direct signal in response to the single phase input signal; and generating an output signal in response to the direct and quadrature signals, such that the output signal is phase locked with the single phase input signal.

Abstract: A method for processing electrical signals includes the steps of: storing a plurality of first digital data signals each representative of an instantaneous amplitude of a first input signal in a memory; selecting one of the first digital data signals in response to a second input signal; combining the selected one of the first digital data signals with a second digital data signal representative of a subsequent instantaneous amplitude of the first input signal, to produce a digital difference signal; producing a first output signal in response to the digital difference signal; and combining the digital difference signal and the selected first digital data signal to produce a modified digital data signal and for replacing the selected one of the first digital data signals with the modified digital data signal in the memory. The method can be performed by an equalizer in a circuit for compensating for amplitude variations in a radio frequency signal or by a comb notch filter.

Abstract: A TFEL edge emitter assembly has a TFEL edge emitter module composed of a substrate and an EL stack supported on the substrate and having a light-emitting front edge, and a covering of solid material overlying the EL stack and attached to the substrate. The solid covering produces a hermetical seal with the substrate which substantially encompasses the EL stack and provide an optically transparent medium having a refractive index between that of the EL stack and air.

Abstract: Push-pull flux quantum superconducting digital logic circuits are provided with a circuit branch having a pair of Josephson junctions electrically connected in series with each other. This circuit branch is connected between positive and negative bias voltage supplies which supply a bias current to the Josephson junctions. A dual polarity input voltage signal is applied to a node in the circuit branch and an output signal is extracted from a second node in the circuit branch. Various logic operations can be performed on the input signal by adding additional components and changing the points at which voltage is input to and output from the Josephson junction circuit branch.

Abstract: Push-pull flux quantum gate array cells synchronously process a pair of polarized data signals. These polarized data signals can be derived from dual polarity data signals by separating the input signals into positive polarity data signals and negative polarity data signals. At least one logic or arithmetic operation is performed on each of the positive and negative polarity signals to produce modified positive and negative polarity signals respectively. These modified positive polarity and negative polarity signals can also be combined to produce a modified dual polarity output data signal. Numerous logic operations can be achieved in gate array cells which perform this signal processing method. By using push-pull flux quantum circuits, the need for auxiliary timing signals or interferometers is minimized.