Abstract: This invention provides a method of broadcasting including the steps of providing a broadcast signal in a central frequency band of an FM radio channel; providing a first plurality of sub-carriers in an upper sideband of the FM radio channel; providing a second plurality of sub-carriers in a lower sideband of the FM radio channel; modulating a first group of the first plurality of sub-carriers with a complementary punctured convolution coded encoded version of program material; modulating a first group of the second plurality of sub-carriers with the complementary punctured convolution coded version of the program material; and transmitting the broadcast signal, the first group of the first plurality of sub-carriers and the first group of the second plurality of sub-carriers. In an all-digital version of the invention, the central frequency band may include a plurality of sub-carriers transmitted at a lower power level than that of the sub-carriers in the upper and lower sidebands.

Abstract: A voltage tunable dielectric varactor includes a substrate having a first dielectric constant and having generally a planar surface, first and second electrodes positioned on the generally planar surface of the substrate, the first and second electrodes being separated to form a first gap therebetween; a tunable dielectric layer positioned on the first and second electrodes and in the first gap, the tunable dielectric layer having a second dielectric constant greater than the first dielectric constant; and third and fourth electrodes positioned on a surface of the tunable dielectric layer opposite the first and second electrodes, the third and fourth electrodes being separated to form a second gap therebetween.

Abstract: A method is provided for identifying a training baud in a digital audio broadcasting signal. The method includes the steps of receiving a plurality of carrier signals modulated by a plurality of data baud, wherein the data baud include normal baud and training baud. The data baud received on the carriers are compared with predetermined data signals to produce a plurality of difference signals. The difference signals are then used to produce a plurality of distance signals, which are combined to produce group distance signals. One of the group distance signals is selected and used to determine if the data baud corresponding to the selected group distance signal is a training baud or a normal baud. This determination is performed by storing successive selected group distance signals until at least one training baud has been received, and using the stored group distance signals to determine normal/training synchronization.

Abstract: A tunable dielectric structure includes a first layer of dielectric material, a second layer of dielectric material positioned adjacent to the first layer of dielectric material, with the second layer of dielectric material having a dielectric constant that is less than the dielectric constant of the first layer of dielectric material, and electrodes for applying a controllable voltage across the first dielectric material, thereby controlling a dielectric constant of the first dielectric material, wherein at least one of the electrodes is positioned between the first and second layers of dielectric material. The dielectric materials can be formed in various shapes and assembled in various orientations with respect to each other. The tunable dielectric structure is used in various devices including a coaxial cables, cavity antenna, microstrip lines, coplanar lines, and waveguides.

Abstract: A phased array antenna includes a plurality of radiating elements, a feed line assembly, a ground plane positioned between the plurality of radiating elements and the feed line assembly, with the ground plane having a plurality of openings positioned between the plurality of radiating elements and the feed line assembly, and a plurality of voltage tunable dielectric phase shifters coupled to the feed line assembly.

Abstract: A varactor comprising a substrate, a first conductor positioned on a surface of the substrate, a second conductor positioned on the surface of the substrate forming a gap between the first and second conductors, a tunable dielectric material positioned on the surface of the substrate and within the gap, the tunable dielectric material having a top surface, with at least a portion of said top surface being positioned above the gap opposite the surface of the substrate, and a first portion of the second conductor extending along at least a portion of the top surface of the tunable dielectric material. The second conductor can overlap or not overlap a portion of the first conductor.

Abstract: A broadcasting method comprising the steps of encoding program material using codes including a first set of bits and a second set of bits, the first set of bits contributing a greater coding gain to the codes than the second set of bits, modulating a plurality of orthogonal frequency division multiplexed carrier signals with the codes, whereby the first set of bits are carried by a first group of the carrier signals and the second set of bits are carried by a second group of the carrier signals, the first group of carrier signals being less susceptible to interference than the second group of carrier signals, broadcasting the carrier signals, receiving the carrier signals, estimating the interference to which the carrier signals in the second group have been subjected to determine if carrier signals in the second group have been corrupted, erasing bits carried by any of the carrier signals which have been determined to be corrupted, and decoding bits of the codes that have not been erased.

Abstract: A method for weighting orthogonal frequency division multiplexed soft symbols is provided, including the steps of receiving a plurality of sub-carriers modulated by digital information and filtering the sub-carriers to produce complex soft decision outputs. The magnitudes of the soft decision outputs are used to creating a first sequence of data. The differences between successive samples in the first sequence are used to create a second sequence of data. The first and second sequences are filtered and compensated for differences in effective group delay of the first and second sequences to produce third and fourth sequences. Then these third and fourth sequences are used to determine a plurality of weights and the weights are applied to the complex soft decision outputs. A receiver which incorporates the method is also disclosed.

Abstract: A method of demodulation and equalization is used to process an amplitude modulated compatible digital broadcasting signal including an amplitude modulated radio frequency signal having a first carrier modulated by an analog program signal in a first frequency spectrum, a plurality of digitally modulated carrier signals positioned within a bandwidth which encompasses the first frequency spectrum, a first group of the digitally modulated carrier signals including complementary carrier signals and lying within the first frequency spectrum, and second and third groups of the digitally modulated carrier signals including non-complementary carrier signals and lying outside of the first frequency spectrum.

Abstract: A method is provided for equalizing an amplitude modulated compatible digital broadcasting signal which includes an amplitude modulated radio frequency signal having a first frequency spectrum, the amplitude modulated radio frequency signal having a first carrier modulated by an analog program signal, a plurality of digitally modulated carrier signals positioned within a bandwidth which encompasses the first frequency spectrum, a first group of the digitally modulated carrier signals including complementary signals and lying within the first frequency spectrum, and second and third groups of the digitally modulated carrier signals including non-complementary signals and lying outside of the first frequency spectrum.

Abstract: This invention relates to an automated method for identifying matches between a set of predetermined traits and a set of preferences. This method can be used to find compatible matches in a variety of situation s where participants are identified by a profile of traits and a set of criteria desired in at match, including, for example, matching candidates to residency program, and matching job hunters with employment opportunities. The present invention offers advantages and improvements over prior computer matching systems because, it provides an automated, effective method for matching traits with corresponding preferences and insures that only matches of the highest degree are made. The, present invention utilizes two-way matching of selected criteria, which measures not only how compatible the potential match is with the desired traits of the user, but also how well the user fits the potential match's idea of the perfect match.

Abstract: This invention provides a method for reducing FM interference in an in-band on-channel digital audio broadcasting system. The method includes the steps of receiving a composite signal including a signal of interest and an interfering signal and normalizing the composite signal to produce a normalized composite signal. The composite signal is then multiplied by the complex conjugate of the normalized composite signal to produce a real signal. Then the real signal is filtered and the resulting filtered signal is multiplied by the normalized composite signal to produce an output signal. The adverse effects of the interfering signal in the output signal are reduced with respect to the magnitude of the signal of interest reducing FM interference in an in-band on-channel digital audio broadcasting system, thereby making it easier to detect the signal of interest.

Abstract: A method for AM in-band-on-channel (IBOC) digital audio broadcasting (DAB) uses a center channel signal in a central frequency band of an AM radio channel, the center channel signal is modulated by first and second versions of the program material to be transmitted. Sub-carriers in a upper and lower sidebands of the AM radio channel are modulated with addition digitally encoded portions of the program material. The upper sideband lies within a frequency band extending from about +5 k Hz to about +10 kHz from a center frequency of the radio channel and the lower sideband lying within a frequency band extending from about −5 k Hz to about −10 kHz from the center frequency of the radio channel. The center channel signal the upper and lower sideband sub-carriers are transmitted to receivers.

Abstract: A system (100) is provided wherein a primary radio signal and a redundant radio signal are transmitted from a transmitter subsystem (120) and received by a receiver subsystem (140). The output (112) of an audio source (110) is coupled to a modulator (160) for modulating a radio frequency signal (162) for coupling to a transmit antenna (172). A second output (114) of audio source (110) is coupled to a delay circuit (116), for adding a predetermined time delay thereto. The delayed audio source signal is coupled to a modulator (164) for modulating a second radio frequency signal (166) that is also coupled to the transmit antenna (172). The receiver subsystem (140) receives both the primary radio signal and the delayed redundant radio signal and couples each to a respective demodulator (180, 182). At least one demodulator (180) includes a circuit (181) for determining the degradation in the primary radio signal and provides a quality measurement output signal (186) to a blend control circuit (190).

Abstract: A broadcasting method encodes program material using convolutional codes having non-puncturable bits and puncturable bits and modulates orthogonal frequency division multiplexed carrier signals with the convolutional codes. The non-puncturable bits are carried by a first group of the carriers and the puncturable bits are carried by a second group of the carriers, where the first group of carrier signals is less susceptible to interference than the second group of carrier signals. The carrier signals are then broadcast to receivers which determine if the carriers in the second group have been corrupted and erase puncturable bits carried by any of the carriers which have been determined to be corrupted. This produces punctured codes which are subsequently decoded to recover the program material.

Abstract: A digital modulation technique, broadcast system, and apparatus for the spectral superposition of an analog AM signal and a novel digitally modulated signal. Multiple mutually orthogonal, continuous-valued noise-like sequences are amplitude and phase modulated. Preferably, modulation coefficients are mapped from the formatted data to be transmitted and basis waveforms are generated which are then modulated by the modulation coefficients. These modulated waveforms may be ASK modulated lowpass waveforms and QAM or in-phase ASK modulated bandpass waveforms. Alternatively, the modulated waveforms may be double sideband QAM modulated lowpass waveforms and QAM modulated bandpass waveforms. In the broadcast system of the present invention, an amplitude modulated signal having a first frequency spectrum is broadcast simultaneously with a plurality of amplitude and/or phase modulated orthogonal noise-like signals having a bandwidth which encompasses the first frequency spectrum.

Abstract: An apparatus and method for generating a broadcast waveform is provided which, for generating an in-phase component, includes an in-phase digital signal generator; a first filter for filtering the in-phase digital signal; a first digital-to-analog converter for converting the filtered digital signal into a first analog signal; an AM baseband signal generator producing an AM baseband signal; a first summer for summing the first analog and AM baseband signals to produce a composite analog signal; and a first modulator for modulating the composite analog signal with a first carrier signal at a transmission frequency, thus producing a first modulated signal.

Abstract: An optical architecture is provided that can be used for generating high-speed input test vectors from low speed digital data and transferrring those test vectors to a device under test. The optical architecture employs gain-switched laser diodes or optical mixers to produce high-speed optical pulses from the low speed digital data. Optical multiplexing and variable delay devices process the high speed optical pulses to form a high-speed test vector. The architecture can generate test data with psec-type accuracy.

Abstract: An arc welding process is provided with a preheating step in which a consumable wire electrode is heated prior to insertion into the electrode stick-out region. This is accomplished by the circulation of current from a preheating power supply through a segment of the wire. Both gas-metal and gas-tungsten arc welding processes are disclosed, along with apparatus used in these processes.