178 results about "Frequency separation" patented technology

A wireless communication system transmits data on multiple carriers simultaneously to provide frequency diversity. Orthogonality is provided by carrier interference, which causes a narrow pulse in the time domain corresponding to each transmitted data symbol. Selection of the frequency separation and phases of the carriers controls the timing of the pulses. Equivalently, pulse waveforms may be generated from an appropriate selection of polyphase sub-carrier codes. Time division of the pulses and frequency division of the carriers may be employed for multiple access. Received signals are processed by combining frequency-domain components corresponding to a desired user's allocated carriers. Individual data symbols are processed by providing polyphase decoding, matched filtering, or time-domain shifting the received carriers. Carrier Interferometry components may be used to build various signals corresponding to other transmission protocols.

A method and system is invented for automated continuous monitoring and real-time analysis of body sounds. The system embodies a multi-sensor data acquisition system to measure body sounds continuously. The sound signal processing functions utilize a unique signal separation and noise removal methodology by which authentic body sounds can be extracted from cross-talk signals and in noisy environments, even when signals and noises may have similar frequency components or statistically dependent. This method and system combines traditional noise canceling methods with the unique advantages of rhythmic features in body sounds. By employing a multi-sensor system, the method and system perform cyclic system reconfiguration, time-shared blind identification and adaptive noise cancellation with recursion from cycle to cycle. Since no frequency separation or signal/noise independence is required, this invention can provide a robust and reliable capability of noise reduction, complementing the traditional methods. The invention further includes a novel method by which pattern recognition of groups of key parameters can be used to diagnosis physical conditions associated with body sounds, with confidence intervals on the diagnostic criterion to indicate accuracy of diagnosis.

There is provided a method of seismic acquisition that utilizes a bank of restricted-bandwidth swept-frequency sub-band sources as a seismic source. Each seismic source will cover a restricted sub-band of frequencies, with all the sources taken together covering the full frequency range. Adjacent frequency bands may partially overlap, but non-adjacent frequency bands should not. The sources may be divided into two or more groups, with no sources covering adjacent frequency bands being placed in the same group. The sources within a group can then be separated by bandpass filtering or by conventional simultaneous source-separation techniques. The source groups may be operated simultaneously but separated in space, and the individual sources themselves may each operate independently, on a sweep schedule customized for that particular source.

A system and method for extending the operating range and/or increasing the bandwidth of a communication link. The communication link may consist of any two communication devices that are connected by two or more separate "band limited" communication paths for the transmission of information therebetween. In operation, the communication devices use a "frequency split scheme" to divide the information transmitted between the devices into two or more signals, each of which is transmitted over one of the communication paths. A "frequency foldback scheme" may also be used to shift the information from the higher frequencies to the lower frequencies of each respective signal, thereby taking advantage of the fact that more information can be carried in the lower frequencies. By using these schemes, it is possible to extend the operating range of the communication link and/or transmit a greater amount of information over the communication paths to thereby increase the bandwidth of the communication link.

A jammer for jamming communications in a communications system where the communications system operates with digital bursts having burst periods measured in time and occurring in a communication frequency band such as GSM having a transmit band and a receive band. The jammer includes a tone comb generator for providing repetitions of jamming signals for the communication frequency band where the jamming signals have jamming signal intervals providing frequency separation between the jamming signals. The jamming signals are generated with a dwell time substantially less than a burst period for the communications system. The jamming signals are generated concurrently for the transmit band and the receive band and are transmitted as RF jamming signals to jam communications for mobile stations.

A method of dynamically allocating RF communication channels to a wireless communication device (102). A plurality of dynamic spectrum allocation (DSA) channels (222, 224) can be identified. The DSA channels can be channels that are available to a non-incumbent user to be used for RF communications. Based on at least one required channel parameter, a DSA channel can be selected as a first channel to allocate to the wireless communication device. At least a second channel can be selected to allocate to the wireless communication device based on a spectral relationship between the first channel and the second channel to ensure that the first and second channels are separated by at least a minimum required frequency separation (216).

Methods and systems for carrying different signals required for MIMO communication using a single coaxial cable between two endpoints of a distributed antenna system (DAS) network. Original MIMO signals having the same frequency are frequency-separated at a first endpoint of the network. The frequency-separated signals are propagated together over the single coaxial cable and then reconstructed to their original frequency at a second endpoint of the network.

A method of determining at least one parameter of a waveguide (3) from wavefield data acquired from wave propagation in the waveguide including obtaining first and second dispersion curves (9a, 9b, 9c) in the frequency domain from the wavefield data. A frequency interval between the first dispersion curve and the second dispersion curve is found, and this is used in the determination of at least one parameter of the waveguide. The frequency separation Δƒ(V) between the first and second dispersion curves may be found at a particular value of the phase velocity V, and the thickness h of the waveguide can be found using:

Here, c₁ is the velocity of wave propagation in the waveguide. This may be found from the asymptotic velocity values of the dispersion curves.

An apparatus including at least one processor and at least one memory including computer program code the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to select at least two single frequency components; generate an indicator, the indicator being configured to represent the at least two single frequency components and is configured to be dependent on the frequency separation between the two single frequency components.

A method for transmitting a signal over a power line channel and a corresponding power line communication modem, wherein the signal is OFDM-modulated on a set of sub-carriers, the sub-carriers being separated by a frequency separation. The method includes receiving a noise signal via the power line channel, determining respective signal values of the received noise signal within a plurality of fine frequency bands with a first resolution bandwidth, wherein the first resolution bandwidth is smaller than the frequency separation, determining a first disturbed frequency band of the plurality of fine frequency bands based on the respective signal values, and notching the signal in the first disturbed frequency band before transmitting the signal.

In servomechanisms, like for example used in disk drives, disturbances, for example, friction, shock and vibration, prevent the system positioning accuracy from further improvement. These disturbances occur in a relatively low-frequency range compared to the electrical dynamics. In the present invention, an acceleration feedback control loop using a frequency-separated acceleration soft sensor (350) replaces the conventionally used current control loop in the low frequency range, where the disturbances occur, so as to attenuate the influence of the disturbances enclosed in the loop. The current feedback continues to manage the electrical dynamics in the high-frequency range. Estimating the required acceleration signal by a soft sensor (350) eliminates the need for physical accelerometers, which reduce system reliability and increase system cost. The acceleration feedback control loop constructed with the obtained acceleration signal also makes the system more robust to the parameter inaccuracies and variations within the loop. This invention can be easily implemented with either software or hardware.

A receiver comprises equalization circuitry implementing at least first and second gain adaptation loops associated with respective first and second frequency bands. The equalization circuitry in one aspect is operative to identify a pattern in a portion of a received serial data stream, and to perform gain adaptation for the receiver utilizing a particular one of the gain adaptation loops responsive to the identified pattern. For example, the gain adaptation may be performed utilizing a low frequency gain adaptation loop if the detected pattern is of a first type generally associated with a low frequency band, and may be performed utilizing a high frequency gain adaptation loop if the detected pattern is of a second type generally associated with a high frequency band. In other aspects, the first and second gain adaptation loops may be activated in a particular serial order or in parallel.

Methods and apparatus for transmitting communications signals that are both power efficient and effective at avoiding or reducing transmitter-generated receive band noise. An exemplary transceiver apparatus includes a multi-mode transmitter that is configurable to operate in a plurality of operating modes (e.g., a polar mode, a quadrature mode and a hybrid mode), a receiver, and an operating mode controller. The operating mode controller is configured to control which operating mode the transmitter is to operate, depending on one or more of a transmit (Tx) power, receive (Rx) power, the Tx power relative to the Rx power, a level of frequency separation between a Tx frequency band and a Rx frequency band (Tx/Rx band separation), and modulation type employed by the transmitter.

The invention provides a regular linear interference suppressing method based on polynomial fitting, comprising the following steps of: (a) artificially recognizing an apparent velocity range of regular linear interferences; (b) performing frequency separation processing on the acquired seismic data through wavelet transform, thereby obtaining low frequency data and high frequency data; (c) determining an apparent dip range of noise data according to the apparent velocity range of the noise data, performing optimal mid-value scanning of apparent dips, and determining the optimal direction of the regular linear interference at the current apparent dip; (d) performing polynomial fitting on the noise data in the optimal direction of the regular linear interference; (e) repeating the steps (c) and (d) until all regular linear interferences in the low frequency data are fitted out; (f) reducing the fitted regular interference data from the original low frequency data obtained through frequency separation, thereby obtaining low frequency data after the regular interference is suppressed; and (g) obtaining the seismic data after the noise is suppressed according to a polynomial fitting rule from the low frequency data after the regular interference is suppressed and the original high frequency data after frequency separation.

A method of cell search in a wireless communication systems having a plurality of base stations and a mobile station, each of the plurality of base stations serving a separate cell within a service area and transmitting a common primary synchronisation code (PSC) in a primary synchronisation channel within a slot of a radio frame, the method including the steps of: (a) scanning (72) through radio channels in scanning increments corresponding to a standard channel raster; (b) estimating (98) the PSC signal-to-noise ratio of each radio channel; (c) if a PSC signal-to-noise ratio is above a first predetermined threshold level (100), completing a cell search procedure including slot synchronisation, frame synchronisation and scrambling code detection steps for that radio channel; (d) if the cell search procedure is successfully completed (112) for the radio channel in step (c), increasing the scanning increments to the broadcast frequency separation between cells; (e) when all radio channels are scanned in step (d), sorting (74) the scanned radio channels in descending order by PSC signal-to-noise ratio; and (f) performing (76) the cell search procedure on each sorted radio channel in descending order.