410 results about "Frequency selectivity" patented technology

An electromagnetic resonance non-contact power transmission device includes a transmitter including a transmitter resonance element having a mechanism for discretely or continuously varying a resonant frequency, a transmitter excitation element coupled to the transmitter resonance element by electromagnetic induction, and an alternating current source for applying an alternating current at the same frequency as the resonant frequency to the transmitter excitation element, and a plurality of receivers each including a receiver resonance element having a specific resonant frequency, a receiver excitation element coupled to the receiver resonance element by electromagnetic induction, and an output circuit for outputting an electric current induced by the receiver excitation element. Electric power is transmitted selectively from the transmitter to any of the receivers having different specific resonant frequencies by changing the resonant frequency of the transmitter.

Methods and apparatuses for frequency selectivity and frequency translation, and applications for such methods and apparatuses, are described herein. The method includes steps of filtering an input signal, and down-converting the filtered input signal. The filtering and the down-conversion operations are performed in an integrated, unified manner. The apparatus described herein can be implemented as an integrated circuit (IC).

An OFDM signal communication system used in broadband mobile communication, achieves stable operation under severe frequency selective fading environments, giving high quality. The OFDM signal communication system which transmits OFDM signals over the same radio frequency from N transmitting antennas, has an inverse matrix computer for computing an N×N inverse matrix constituted by propagation coefficients for respective propagation paths between each of N transmitting antennas and each of N receiving antennas, and a subcarrier demodulator which separates the signals of the respective propagation paths, based on the obtained inverse matrix.

A system and method for generating transmit weighting values for signal weighting that may be used in various transmitter and receiver structures is disclosed herein. The weighting values are determined as a function of frequency based upon a state of a communication channel and the transmission mode of the signal. In variations, weighting of the weighted signal that is transmitted through each of a plurality of antennas is carried out with one of a corresponding plurality of transmit antenna spatial weights. In these variations, a search may be conducted over various combinations of transmit weighting values and transmit antenna spatial weights in order to find a weight combination that optimizes a performance measure such as the output signal-to-noise ratio, the output bit error rate or the output packet error rate.

A communication is provided that schedules both Distributed Virtual Resource Blocks (DVRB) and Localized Virtual Resource Blocks (LVRB) in a same frequency channel, thereby obtaining the benefits of frequency selective scheduling while minimizing the uplink feedback overhead. In one embodiment of the invention, the communication system assigns one or more downlink Physical Resource Blocks (PRBs) of multiple downlink Physical Resource Blocks (PRBs) to each user equipment (UE) given an LVRB to produce at least one reserved PRB and multiple non-reserved PRBs and assigns a part of each PRB of the multiple non-reserved PRBs to a UE given a DVRB. In another embodiment of the invention, the communication system assigns PRBs pre-reserved for localized transmission to UEs scheduled for LVRBs and assigns parts of multiple PRBs pre-reserved for distributed transmission to each UE given a DVRB.

A method of transmitting feedback data in a multiple antenna system comprises receiving a request message of feedback data on a downlink channel, the request message comprising uplink scheduling information, selecting a set of M (M≧1) subbands within a plurality of subbands, generating the feedback data, the feedback data comprising a frequency selective PMI (preceding matrix indicator), a frequency flat PMI, a best band CQI (channel quality indicator) and a whole band CQI, and transmitting the feedback data on a uplink channel allocated to the uplink scheduling information.

Methods and apparatuses for frequency selectivity and frequency translation, and applications for such methods and apparatuses, are described herein. The method includes steps of filtering an input signal, and down-converting the filtered input signal. The filtering and the down-conversion operations are performed in an integrated, unified manner. The apparatus described herein can be implemented as an integrated circuit (IC). The apparatus may include a module or modules for gain control.

Pressure-isolating bulkhead structures with integrated selective electronic switches circuitry are provided. The pressure-isolating bulkhead structure may be a single unit having the integrated electronic switch circuitry, as well as an electrical connector that includes at least one of a wire and a pin contact. Such integrated selective electronic switch circuitry may be fashioned within a self-contained, inner pressure-isolating enclosure body. Such inner pressure-isolating enclosure body may be produced about the selective electronic switch circuitry such that the inner pressure-isolating enclosure body and switch circuitry are produced as a unit, which can be easily placed within a variety of bulkhead structures, and subsequently within a perforating gun.

A digital signal processing-based receiver architecture performs automatic gain control (AGC) for a frequency hopping spread-spectrum communications receiver that may be subjected to one or more sources of interference or jamming. Rather than set the AGC gain at a fixed, best hoped for value, and then attempt to rely on decoding or interleaving to interpolate lost or degraded data, the present invention, through repeated but aperiodic transitions or hops across a plurality of frequency bins of interest, develops a gain profile for the plurality of frequency bins, and uses the gain profile to adjust, on a hop-by-hop basis, the gain for the channel / bin to which the receiver is listening, so as to maintain the average aggregate input signal power at an optimal ADC loading factor.

A new digital architecture for metallic pipe and cable locators, providing accurate estimation of the fundamental locate parameters, electromagnetic signal strength and signal direction, and utilizing a nested Digital Phase-Locked Loop (DPLL) structure is disclosed. The obstacles to signal direction measurement in low SINR environments using the signal select method are overcome and a more precise phase comparison between the carrier and the FM modulation signals is obtained. The architecture further significantly reduces analog front-end hardware requirements, offers wider resistance to component tolerances, lower calibration and test time, and provides flexible frequency selectivity. Locators according to the present invention provide accurate estimation of the fundamental physical parameters of line location (electromagnetic signal strength and signal direction) in extremely noisy environments, using Digital Signal Processing (DSP) methods.

A quadrifilar antenna having helical windings is fed by a phase shift feed network, each winding having an open circuit termination element, the phase shift feeding network having forward directional phase shift paths from a feed input to phase shift feed output ports, and having a first reverse directional transmission path from one or more of the phase shift feed output ports back to a first isolation port, and a second reverse directional transmission path from another one or more of the phase shift feed output ports back to a second isolation port, the first and second isolation ports isolated from the forward directional phase shift paths, and a differential termination impedance, floating from ground, connected the first and second isolation ports. Optionally, the differential termination impedance is frequency selective.

A process and device for detecting electrically conductive particles in a liquid flowing in a pipe section, the liquid being exposed to periodic alternating electromagnetic fields by a transmitter coil which induces eddy currents in the particles, a probe made as a coil arrangement and which has an effective width producing a periodic electrical signal based on the eddy currents. The signal ha a carrier oscillation with an amplitude and / or phase which is modulated by particles passing across the effective width of the coil arrangement, the probe signal being filtered by a frequency-selective first filter unit, the filtered signal being sampled by a triggerable A / D converter stage to obtain a demodulated digital measurement signal, the digital measurement signal being filtered by a digital, frequency-selective adjustable second filter unit to obtain a useful signal, and the useful signal being evaluated to detect passage of electrically conductive particles in the pipe section.

Techniques are described for channel estimation of block transmissions over time- and frequency-selective wireless fading channels. A wireless transmitter forms blocks of symbols that include at least two blocks of training symbols separated by at least one information-bearing symbol. Each block of training symbols comprises a first block of zero symbols and a second block of zero symbols separated by at least one training symbol. Each block of training symbols is equally long and equally spaced between information-bearing symbols. The training and information-bearing symbols are transmitted with equal power, respectively. A wireless receiver receives a wireless transmission signal formed according to the blocks of symbols and forms an estimate of a wireless communication channel based on the training symbols within the received signal. The structure and selected parameters of the symbols enabling symbol detection and channel estimation to be decoupled at the receiver while maximizing the average capacity of the channel.

In an Orthogonal Frequency Division Multiplexing communication system wherein a frequency bandwidth is divided into multiple sub-bands, a method and a scheduler is provided for configuring channel quality feedback for a point-to-multipoint communication session involving multiple users equipment (UEs). The scheduler receives multiple channel quality measurements from the multiple UEs and, based on the multiple channel quality measurements, determines whether to implement a frequency selective channel quality feedback scheme or a non-frequency selective channel quality feedback scheme for the point-to-multipoint communication session. The scheduler then implements the determined channel quality feedback scheme. In another embodiment of the invention, the scheduler may determine whether to implement a frequency selective or non-frequency selective channel quality feedback scheme based on a number of UEs serviced by the scheduler.

The radiation properties and wave guiding properties of frequency selective surfaces are used in conjunction with closely spaced antenna elements to fabricate antenna structures having adjustable radiation characteristics. The direction, magnitude, and polarization of radiation patterns for such antenna structures can be adjusted by varying the texture or patterning of layers of conducting material forming the frequency selective surfaces. The invention enables the fabrication of low profile antenna structures that can easily be conformed or integrated into complex surfaces without sacrificing antenna performance.

The invention discloses a dual-polarized filter antenna with high selectivity and low cross polarization. The dual-polarized filter antenna comprises a metal reflecting floor at the bottom part, a middle feed patch, a parasitic patch at the top part, a first dielectric substrate, a second dielectric substrate and two sections of feed lines, wherein the parasitic patch is printed on the upper surface of the first dielectric substrate; the feed patch is printed on the upper surface of the second dielectric substrate; and the two sections of feed lines are orthogonally coupled and are printed on the lower surface of the second dielectric substrate. The feed structure disclosed by the invention can generate one zero point at a passband low-frequency band of the antenna; meanwhile, the designed parasitic patch generates one zero point at a passband high-frequency band; and the two zero points provide good band-pass filtering and frequency selectivity effects.

A time division duplex wireless communication system based on Code Spreading-Orthogonal Frequency Division Multiple Access (CS-OFDMA) and a smart antenna includes: an antenna array and multichannel transceiver, a space processor, a demodulator, an L2 processor and a modulator. The CS-OFDMA system provided by the present invention combines synchronous CDMA technique and OFDMA technique, overcomes the severe ISI caused by spectrum-spreading by the conventional CDMA system while transmitting wideband data, effectively counteracts frequency-selective fading and inter-cell interference, and is beneficial to reliable transmission of narrowband voice and wideband data and also beneficial to co-frequency networking.

A receiving method and a direct conversion receiver are provided. The receiver comprises a mixer (308) for mixing a received signal into a base band signal com-prising I and Q branches, and an A / D converter (316) for converting the base band signal into digital form, and a phase adjuster (318) for performing a frequency selective IQ phase error estimation and for correcting the digitised signal with frequency selective correction factors based on the error estimation.

Disclosed is a system and method for selective email processing. A traffic separator includes an interface for receiving electronic mail traffic from a source network address. The traffic separator also includes a processor for comparing the source network address to a stored list of network addresses to determine a categorization of the network source address. The traffic separator also includes at least one interface for forwarding the electronic mail traffic to one of many message transfer agents (MTAs) based upon said determination. A database stores the list of network addresses. In one embodiment, one or more network addresses in the stored list are network address ranges.

Disclosed herein are various high-impedance surfaces having high capacitance and inductance properties. One exemplary high-impedance surface includes a plurality of conductive structures arranged in a lattice, wherein at least a subset of the conductive structures include a plurality of conductive plates arranged along a conductive post so that the conductive plates of one conductive structure interleave with one or more conductive plates of one or more adjacent conductive structure. Another exemplary high-impedance surface includes a plurality of conductive structures arranged in a lattice, where the conductive structures include one or more fractalized conductive plates having either indentions and / or projections that are coextensive with corresponding projections or indentations, respectively, of one or more adjacent conductive structures. Also disclosed are various exemplary implementations of such high-impedance surfaces.

The invention discloses a micro-strip rectangular double annular circular-seam resonator-based frequency selectivity surface structure, which comprises a micro-strip rectangular double annular circular-seam resonator unit and a medium substrate, wherein a micro-strip rectangular double annular circular-seam resonator is arranged on one side or both sides of the medium substrate or clamped betweenmedium layers, and is provided with circular seams in different directions. In a working process, electromagnetic waves in different directions enter the frequency selectivity surface structure. The structure has the advantages of small size, adjustable resonance frequency, capability of realizing omnidirectional response to electromagnetic waves and the like.

A frequency selective leveling loop that performs phase and amplitude control of multiple signals within a phased array structure is disclosed. The leveling loop sensor componants are embedded into the array structure. The frequency selective leveling loop can be used with multiple signal amplifiers, and a conventional phase array jamming system can be used to radiate multiple signals simultaneously. The conversion of phase information to baseband eliminates the need for phase matched cables. The frequency selective leveling that is enabled is tolerant of multiple signals and provides the individual signal phase and amplitude feedback by utilizing analytic sampling.

A method of transmitting feedback data in a multiple antenna system comprises receiving a request message of feedback data on a downlink channel, the request message comprising uplink scheduling information, selecting a set of M (M≧1) subbands within a plurality of subbands, generating the feedback data, the feedback data comprising a frequency selective PMI (preceding matrix indicator), a frequency flat PMI, a best band CQI (channel quality indicator) and a whole band CQI, and transmitting the feedback data on a uplink channel allocated to the uplink scheduling information.

A high-speed communications system utilizes approximate bit-loading during data transmission in a channel. In one embodiment, a plurality of parallel data preparation circuits in a data transmission circuit receive respective subsets of a data stream, each of the respective subsets of the data stream having a data rate that is less than a data rate of the data stream. Converters in the data preparation circuits convert the respective subsets of the data stream into respective analog signals. Multipliers in the data preparation circuits multiply the respective analog signals by respective vectors to produce respective sub-channel signals. At least a frequency band in the spectrum corresponding to one of the respective sub-channel signals partially overlaps at least a frequency band for at least one other of the respective sub-channel signals. The respective sub-channel signals are combined prior to transmission.

Decoupling circuits are provided which transfer energy induced from an MRI pulsed RF field to the housing for an active implantable medical device (AIMD) which serves as an energy dissipating surface. This is accomplished through broadband filtering or by resonant filtering. In a passive component network for an AIMD, a frequency selective energy diversion circuit is provided for diverting high-frequency energy away from an AIMD lead to the AIMD housing for dissipation of said high-frequency energy.

An antenna (100) for microwave radiation including a first horn (135) which includes a plurality of corrugations (150). At least one of the corrugations (150) is formed of a frequency selective surface (FSS) (138). The FSS has a plurality of FSS elements (305) coupled to at least one substrate (310). The substrate (310) can define a first propagation medium such that an RF signal having a first wavelength in the first propagation medium can pass through the FSS (300). The FSS (300) is coupled to a second propagation medium such that in the second propagation medium the RF signal has a second wavelength which is at least twice as long as a physical distance between centers of adjacent FSS elements (305).

A transmitter for reducing time selectivity and / or frequency selectivity in a wireless communication system includes a plurality of transmit antennas, a phase shifter which is disposed for each transmit antenna and is configured to shift a phase of data transmitted through the transmit antenna by a phase shift value, and a channel selectivity processor configured to obtain the phase shift value by using a channel phase value fed back from a receiver.

A method, system, and base station for providing subband signal to noise ratio (SNR) correction in the scheduling of communication resources. A Scheduling Correction (SC) utility receives periodic subband and wideband channel quality indicator (CQI) reports from one or more wireless devices. The SC utility records a subframe report period for a respective subband CQI report. The SC utility calculates the age of the subband report to determine whether the subband CQI report remains valid. If the subband report is invalid, the SC utility utilizes the wideband CQI report for (current) transmission scheduling. However, if the subband report is valid, the SC utility utilizes: (a) the subband CQI report for transmission scheduling from the most current reporting subframe; or (b) a modified subband CQI value with a correction that utilizes the wideband CQI report, if the subband CQI report was not received at the most current reporting subframe.

A communication system for transmitting encoded signals over a communication channel is disclosed. The system includes a transmitter, which has a source that outputs a message signal. The transmitter also includes an encoder that generates a code word in response to the message signal. The code word has a construction that defines a plurality of paths associated with an intersymbol interference (ISI) environment of the communication channel, wherein the code word achieves a diversity based upon the number of transmit antennas and the number of ISI paths. Further, the transmitter includes a modulator that modulates the code word for transmission over the communication channel, and multiple antennas that transmit the modulated code word over the communication channel. The system encompasses a receiver that receives the transmitted code word via a number of receive antennas.