1052 results about "Sideband" patented technology

A resonant grating structure in a waveguide and methods of tuning the performance of the grating structure are described. An apparatus includes a waveguide; and a subwavelength resonant grating structure embedded in the waveguide. The systems and methods provide advantages including narrowband filtering capabilities, minimal sideband reflections, spatial control, high packing density, and tunability.

A class of bandwidth reduction techniques are used develop a broad class of modulation types collectively called SSB-FM. These signals can be used to construct communication systems that provide bandwidth-normalized performance gains of 10 dB or more when compared to popular prior art modulation methods. An aspect of the invention involves mapping trellis paths in a complex signal space onto corresponding real-valued trellis signals with desirable spectral properties. The invention can be used map continuous phase modulated (CPM) signals onto simpler amplitude-modulated trellis signals having double the channel capacity of prior art CPM signals. Multi-amplitude signaling and frequency division multiplexing may also be incorporated to further accommodate more information per symbol.

Optical transmitters for radio over fiber systems are disclosed. More particularly, the optical transmitters include optically-injection-locked vertical cavity surface-emitting laser devices (OIL VCSELS). The transmitters include a master laser, at least one slave laser injection-locked by the master laser, and an equalizer/filter unit that enables the ratio of the carrier power to the sideband power in the output signal of the transmitter to be varied and optimized independently of the injection ratio of the transmitter.

An optical frequency comb generator includes a laser device arranged for generating input laser light having a predetermined input light frequency, a dielectric micro-resonator having a cavity exhibiting a third order nonlinearity, so that the micro-resonator is capable of optical parametric generation providing parametrically generated light, and a waveguide optically coupled to the micro-resonator, the waveguide being arranged for in-coupling the input laser light into the micro-resonator and out-coupling the parametrically generated light out of the micro-resonator, wherein the laser device, the waveguide and the micro-resonator being arranged for resonantly in-coupling the laser input light to a mode of the micro-resonator with a minimum power level so that an optical field inside the cavity exceeds a predetermined cascaded parametric oscillation threshold at which the parametrically generated light includes frequencies of frequency sidebands of the input light frequency and of the sidebands thereof.

A system for transmitting digital programming includes a program source providing digital information, circuitry for modulating the digital information onto a visual carrier modulated with analog television programming, and a visual transmitter coupled to the modulating circuitry. Using a phase modulation method, the system phase modulates the digital information onto a visual carrier, reduces the baseband frequencies of the phase modulated visual carrier, and amplitude modulates the phase-modulated video carrier onto a video signal. The amplified and encoded video signal are combined with an amplified sound signal and transmitted. Using an additive method, the system modulates the sidebands of the video carrier with the digital information and amplitude modulates the video signal onto the video carrier. The data-modulated sidebands are phase-shifted such that they will be in quadrature with the amplitude-modulated video signal. The system combines the amplitude-modulated video carrier and the data-modulated quadrature sidebands. With a blended multiplicative/additive method, the system provides phase modulation and quadrature sideband addition to provide an optimized result. Process, systems, circuits and devices for abating or otherwise correcting effects of the information on the analog television signal are also disclosed.

Methods and apparatus are disclosed for handling fatal computer hardware errors on a computer that include halting data processing operations of the computer upon occurrence of a fatal hardware error; signaling by a source chip of a chipset to the programmable logic device the occurrence of a fatal hardware error; signaling by the programmable logic device to an embedded system microcontroller the occurrence of a fatal hardware error; reading by the embedded system microcontroller through at least one sideband bus from registers in chips of the chipset information regarding the cause of the fatal hardware error; and storing by the embedded system microcontroller the information in non-volatile random access memory of the embedded system microcontroller.

A digital Vestigial Sideband (VSB) transmission system and enhanced data multiplexing method are disclosed. When 1/2 enhanced data coded at a rate of 1/2 and 1/4 enhanced data at a rate of 1/4 are transmitted, timing jitter in Moving Picture Experts Group (MPEG) of Vestigial Sideband (VSB) receiver can be reduced and the size of input buffer in Moving Picture Experts Group (MPEG) decoder of the Vestigial Sideband (VSB) receiver can be reduced by multiplexing the 1/2 enhanced data packet and the 1/4 data packet at predetermined intervals. Multiplexing the 1/2 enhanced data packet and the 1/4 data packet by grouping increases the reception performance of the 1/4 enhanced data. Multiplexing the 1/2 enhanced data packet and the 1/4 data packet alternatively reduces the Moving Picture Experts Group (MPEG) timing jitter in the Vestigial Sideband (VSB) receiver and increases the reception performance of the 1/4 enhanced data.

A digital broadcasting transmission system and method thereof. The digital broadcasting transmission system, comprises an RS encoder to encode a dual transport stream (TS) which includes a normal stream and a plurality of turbo streams multiplexed together, an interleaver to interleave the encoded dual TS, a turbo processor to detect the turbo streams from the interleaved dual TS and to encode the detected turbo stream, and a trellis encoder to pseudo2 (P-2) vestigial sideband (VSB) code the turbo-processed dual TS, and, then, to perform trellis encoding, and a main multiplexer (MUX) to multiplex the trellis-encoded dual TS by adding a field synchronous signal and a segment synchronous signal thereto.

An apparatus includes multiple signal paths for optically converting an optical signal to multiples of the optical signal at different respective carrier frequencies for reducing interference between wireless transmissions of the multiples of the optical signal. Preferably, the converting includes a first modulator for modulating the optical signal into a first optical carrier and an initial first-order sideband signal with a frequency spacing twice that of the first optical carrier and a first interleaver for separating the first optical carrier and the initial first-order sideband signal. The converting also includes a second phase modulator for modulating the first optical carrier into a second optical carrier and a second first-order sideband signal with a frequency spacing twice that of the second optical carrier.

A distributed system structure for a large-way, symmetric multiprocessor system using a bus-based cache-coherence protocol is provided. The distributed system structure contains an address switch, multiple memory subsystems, and multiple master devices, either processors, I/O agents, or coherent memory adapters, organized into a set of nodes supported by a node controller. The node controller receives transactions from a master device, communicates with a master device as another master device or as a slave device, and queues transactions received from a master device. Since the achievement of coherency is distributed in time and space, the node controller helps to maintain cache coherency. The node controller also implements an interrupt arbitration scheme designed to choose among multiple eligible interrupt distribution units without using dedicated sideband signals on the bus.

The present invention relates to a Vestigial Side Band (VSB) Digital Television (DTV) in agreement with the DTV standards (A/53) of the Advanced Television System Committee (ATSC), and to a method thereof. More particularly, it provides 4-VSB DTV transceiver that improves reception performance of a receiver by transmitting and receiving dual streams formed of normal data and robust data without increasing average power, regardless of a mixing rate of the normal and robust data. The 4-VSB DTV transceiver of the present research includes an encoding unit for encoding the robust data to be mapped to one of two groups having 4 levels {−5, −3, 1, 7} and {−7, −1, 3, 5}.

Systems, methods, apparatus and computer program products are provided for signaling a deterministic mapping corresponding to a service. The deterministic mapping is inserted within an in-band ATSC vestigial sideband broadcast signal or an out-of-band signal and transmitted to receivers capable of consuming the service.

A suite of optical performance monitoring (OPM) methods, based on optical subcarrier multiplexing, are described by the invention. The strength of this approach lies in the simplicity of double sideband subcarrier signals and the fact that these signals travel the complete optical path with the baseband signal of interest. The subcarrier signals can be recovered using techniques described in the application and are immune to fiber dispersion induced fading.

A sinusoidal R.F. carrier is modulated for the transmission of digital binary datastreams through the deletion of carrier wavelets. These wavelets are defined between zero crossover positions representing zero energy locations. One or more wavelets are switched out of the carrier at the zero crossing positions to avoid sideband generation occasioned by electromagnetic energy disturbance. Transmissional amplification as well as receptional amplification is carried out with non-resonating amplifier architecture.

A working router is coupled to a SONET add-drop multiplexor (ADM) through a working line and a protection router is coupled to the ADM through a protection line. The routers are coupled to each other by a separate side-band connection and comprise a virtual router from the perspective of the neighboring router, which communicates with the virtual router over the SONET network using the Point-to-Point Protocol (PPP). The protection router transmits a heartbeat message to the working router over the side-band connection. If the protection router does not receive a response thereto, it initiates a line switch within the add-drop multiplexor. Once the line switch is complete, the protection router exchanges datagrams with the neighboring router, via the ADM and SONET ring to which the ADM is coupled. The protection router establishes a PPP connection between itself and the neighboring router device coupled to the SONET ring, utilizing the Link Control Protocol (LCP). The protection router includes a predetermined identifier value that identifies the originator of the request, in the LCP Identifier field of LCP request datagrams. The neighboring router includes the Identifier value received in a request datagram in the corresponding response datagram transmitted over the SONET ring to the ADM. Because datagrams received by the ADM from the SONET link are transmitted over both the working and the protect lines, the working router receives the same response as the protection router. Thus, by examining the identifier field, and recognizing the identifier value as that assigned to the protection router, the working router determines that the line switch to the protection router has occurred.

Circuits and methods of LED dimming are disclosed. Frequency modulation using controlled modulation depth generates deterministic sidebands of both the fundamental frequency and its harmonics. Various filters including low-pass, band-pass, high-pass and combinations of those are used to selectively filter the deterministic frequency components generated by the frequency modulation to achieve LED dimming.

The invention discloses a COTDR (coherent detection based optical time-domain reflectometry) fused long-distance coherent detection brilouin optical time-domain analyzer which comprises a narrow-linewidth laser, two couplings, a microwave signal source, an electro-optic modulator, an isolator, a long-distance sensing optical fiber, an optical circulator, a 3 db coupling, a pulse modulator, an Er-doped fiber amplifier, a scrambler, a pulse signal generator, a balancing photoelectric detector, an electrical frequency spectrum analyzer, a data processing module and an acousto-optic modulator. According to the invention, the signal-to-noise ratio of BOTDA (brilouin optical time domain analysis) is improved by using a coherent detection method, a non-local effect of a BOTDA system is reduced in a double-sideband detection mode, and the sensing distance is more than 70 km under the condition of no light amplification such as raman; and according to the invention, the COTDR is fused to a coherent detection based BOTDA system, and the system can run in a breakpoint testing mode, so that the defect that the traditional BOTDA can not run when a sensing fiber has breakpoints and can not carry out positioning on breakpoints is effectively overcome, thereby enhancing the adaptability and practicability of the sensing system.

A carrier and symbol timing recovery apparatus usable in a VSB (Vestigial Side Band) receiver, and a method thereof. For a carrier and symbol timing recovery, error information is detected using a pilot signal, an upper sideband and a lower sideband of a received signal. Each of the detected error information is multiplied by a predetermined weight, respectively, and the results of the respective multiplications are added/combined. Therefore, even though the pilot signal may be corrupted, the carrier recovery can nevertheless be accurately performed. Additionally, even though the upper sideband of a received VSB-modulated signal may be corrupted, the lower sideband can be utilized to perform the symbol timing recovery. As a result, performance of a receiving system can be improved even under unfavorable channel characteristics. Moreover, since the carrier recovery and the symbol timing recovery are executed through a single apparatus, it becomes possible to simplify a hardware implementation thereof.

A system is provided for implementing PCI Express protocol signals over an optical link. A transmission circuit is used to provide an electrical-to-optical conversion, a receiving circuit provides an optical-to-electrical conversion, and a sideband circuit is used to provide and receive control information.

A method and system for generating and transmitting optical signals with only one sideband. Single-sideband optical signal transmission reduces the signal impairment effects associated with dispersion. Such transmission also increases the spectral efficiency of optical transmission systems. Single-sideband modulation also makes possible electrical compensation for optical link dispersion during transmission. Single-sideband modulation is generated using the modulating data signal and its Hilbert transform, which is approximated by a tapped-delay time filter. Line coding is used to remove the low-frequency content in the modulating data signal, avoiding the inefficiencies of tapped-delay-line filter approximated Hilbert transformers at low frequencies. Line coding can also help optical single side band signal generation and transmission using a simple optical filter instead of Hilbert transformers.

Apparatus and method for amplifying laser signals using segments of fibers of differing core diameters and/or differing cladding diameters to suppress amplified spontaneous emission and non-linear effects such as four-wave mixing (FWM), self-phase modulation, and stimulated Brillouin and/or Raman scattering (SBS/SRS). In some embodiments, different core sizes have different sideband spacings (spacing between the desired signal and wavelength-shifted lobes). Changing core sizes and providing phase mismatches prevent buildup of non-linear effects. Some embodiments further include a bandpass filter to remove signal other than the desired signal wavelength and/or a time gate to remove signal at times other than during the desired signal pulse. Some embodiments include photonic-crystal structures to define the core for the signal and/or the inner cladding for the pump. Some embodiments include an inner glass cladding to confine the signal in the core and an outer glass cladding to confine pump light in the inner cladding.

A multi-core processor includes microcode distributed in each core enabling each core to participate in a de-centralized inter-core state discovery process. In a related microcode-implemented method, states of a multi-core processor are discovered by at least two cores participating in a de-centralized inter-core state discovery process. The inter-core state discovery process is carried out through a combination of microcode executing on each participating core and signals exchanged between the cores through sideband non-system-bus communication wires. The discovery process is unmediated by any centralized non-core logic. Applicable discoverable states include target and composite power states, whether and how many cores are enabled, the availability and distribution of various resources, and hierarchical structures and coordination systems for the cores. The inter-core state discovery process may be carried out in accordance with various hierarchical coordination systems involving chained inter-core communications.

An optical transmitter for an optical fiber transmission system is described. The optical transmitter includes an optical source that generates an optical signal having a wavelength at an output. An optical intensity modulator modulates the optical signal with an electrical modulation signal to generate a modulated optical signal at an output. At least one parameter of the optical intensity modulator is chosen to suppress at least one of phase and sideband information in the modulated optical signal. An optical fiber is coupled to the output of the optical intensity modulator. The suppression of the at least one of the phase and the sideband information in the modulated optical signal increases an effective modal bandwidth of the optical fiber.

A single-axis receiver processing, for example, complex vestigial sideband modulated signals with an equalizer with forward and feedback filters. Forward and feedback filters have parameters that are initialized and adapted to steady state operation. Adaptive equalization employs linear predictive filtering and error term generation based on various cost criteria. Adaptive equalization includes recursive update of parameters for forward and feedback filtering as operation changes between linear and decision-feedback equalization of either single or multi-channel signals. An adaptive, linear predictive filter generates real-valued parameters that are employed to set the parameters of the feedback filter. In an initialization mode, filter parameters are set via a linear prediction filter to approximate the inverse of the channel's impulse/frequency response and a constant modulus error term for adaptation of the filter parameters. In an acquisition mode, equalization is as linear equalization with a constant modulus error term, and possibly other error terms in combination, for adaptation of the filter parameters. In a tracking mode, equalization is as decision feedback equalization with decision-directed error terms for adaptation of the filter parameters. For some equalizer configurations, feedback filtering is applied to real-valued decisions corresponding to complex-valued received data, and includes real-part extraction of the error term employed for recursive update of filtering parameters. Where a training sequence is available to the receiver, initial parameters for forward filtering are estimated by correlation of the received signal with the training sequence.

A ground-penetrating radar comprises a software-definable transmitter for launching pairs of widely separated and coherent continuous waves. Each pair is separated by a constant or variable different amount double-sideband suppressed carrier modulation such as 10 MHz, 20 MHz, and 30 MHz Processing suppresses the larger first interface reflection and emphasizes the smaller second, third, etc. reflections. Processing determines the electrical parameter of the natural medium adjacent to the antenna.

The modulation process may be the variable or constant frequency difference between pairs of frequencies. If a variable frequency is used in modulation, pairs of tunable resonant microstrip patch antennas (resonant microstrip patch antenna) can be used in the antenna design. If a constant frequency difference is used in the software-defined transceiver, a wide-bandwidth antenna design is used featuring a swept or stepped-frequency continuous-wave (SFCW) radar design.

The received modulation signal has a phase range that starts at 0-degrees at the transmitter antenna, which is near the first interface surface. After coherent demodulation, the first reflection is suppressed. The pair of antennas may increase suppression. Then the modulation signal phase is changed by 90-degrees and the first interface signal is measured to determine the in situ electrical parameters of the natural medium.

Deep reflections at 90-degrees and 270-degrees create maximum reflection and will be illuminated with modulation signal peaks. Quadrature detection, mixing, and down-conversion result in 0-degree and 180-degree reflections effectively dropping out in demodulation.

Methods and systems for producing an encoded information signal having attenuated low frequency spectral components and a substantially constant average energy. An M bit code word is produced for each N bits of an information signal according to the following conditions: (a) each code word includes an equal number of logic zero bits and logic one bits; (b) each code word includes no more than two consecutive identical bits; and (c) M is greater than N. For example, M equals eight and N equals four. Such an encoded information signal is especially useful for generating a magnetic field signal usable for locating an underground object. This is in part because information sidebands of the magnetic field signal to have desired spectral characteristics that are useful in environments that often include harmonically derived interference signals at regular 50 Hz (±0.1 Hz) or 60 Hz (±0.1 Hz) intervals caused by power lines.

A sideband scout thread processing technique is provided. The sideband scout thread processing technique utilizes sideband information to identify a subset of processor instructions for execution by a scout thread processor. The sideband information identifies instructions that need to be executed to "warm-up" a cache memory that is shared with a main processor executing the whole set of processor instructions. Thus, the main processor has fewer cache misses and reduced latencies. In one embodiment, a system includes a first processor for executing a sequence of processor instructions, a second processor for executing a subset of the sequence of processor instructions, and a cache shared between the first processor and the second processor. The second processor includes sideband circuitry configured to identify the subset of the sequence of processor instructions to execute according to sideband information associated with the sequence of processor instructions.

There is disclosed an improved system and method for providing frequency domain synchronization for a single carrier signal such as a vestigial sideband signal. The system comprises a synchronization circuit that is capable of obtaining a coarse frequency estimate of the single carrier signal and a fine frequency estimate of the single carrier signal. The system also comprises a three state machine for obtaining an accurate frequency estimate from three separately obtained frequency estimates. The system also comprises a DC estimator circuit that is capable of providing a time domain DC estimate. The system provides a pilot carrier recovery circuit for single carrier signals that has a linear transfer function.

A circuit module for a phased array (10) incorporates radio frequency (RF) mixers (54a, 54b) connected to an RF splitter/combiner (52) and to in-phase and quadrature RF reference signals. The RF mixers (54a, 54b) are also connected to intermediate frequency (IF) processing circuitry (60 to 68) providing for phase control of RF signals and IF reference signals. In transmission mode, the RF mixer (54a, 54b) receive phase-controlled, digitally synthesised IF signals from clock-activated generators (68a, 68b). Their outputs are combined at the RF splitter/combiner (52) to provide single sideband upconversion of the phase-controlled IF signals. In reception mode, the RF splitter/combiner (52) and the RF mixers (54a, 54b) act as an image rejection mixer circuit in which the phase-controlled IF signals are local oscillator signals. Beamforming is carried out by computer control of the IF phase together with, in the case of reception, analogue or digital summation of output signals from an array of modules (12).

PCT No. PCT/GB95/01607 Sec. 371 Date Dec. 10, 1997 Sec. 102(e) Date Dec. 10, 1997 PCT Filed Jul. 7, 1995 PCT Pub. No. WO97/03367 PCT Pub. Date Jan. 30, 1997A circuit module for a phased array radar (10) incorporates radar frequency (RF) mixers (54a, 54b) connected to an RF splitter/combiner (52) and to in-phase and quadrature RF reference signals. The RF mixers (54a, 54b) are also connected to intermediate frequency (IF) processing circuitry (60 to 68) providing for phase control of RF signals and IF reference signals. In transmission mode, the RF mixer (54a, 54b) receive phase-controlled, digitally synthesised IF signals from clock-activated generators (68a, 68b). Their outputs are combined at the RF splitter/combiner (52) to provide single sideband upconversion of the phase-controlled IF signals. In reception mode, the RF splitter/combiner (52) and the RF mixers (54a, 54b) act as an image rejection mixer circuit in which the phase-controlled IF signals are local oscillator signals. Beamforming is carried out by computer control of the IF phase together with, in the case of reception, analogue or digital summation of output signals from an array of modules (12).