813 results about "Frequency interval" patented technology

A method of modulating communications signals, such as optical fiber, wired electronic, or wireless signals in a manner that facilitates automatic correction for the signal distortion effects of echoes and frequency shifts, while still allowing high rates of data transmission. Data symbols intended for transmission are distributed into N×N matrices, and used to weigh or modulate a family of cyclically time shifted and cyclically frequency shifted waveforms. Although these waveforms may then be distorted during transmission, their basic cyclic time and frequency repeating structure facilitates use of improved receivers with deconvolution devices that can utilize the repeating patterns to correct for these distortions. The various waveforms may be sent in N time blocks at various time spacing and frequency spacing combinations in a manner that can allow interleaving of blocks from different transmitters. Applications to channel sounding / characterization, system optimization, and also radar are also discussed.

The present invention is embodied in a system and method for performing spectral analysis of a digital signal having a discrete duration by spectrally decomposing the digital signal at predefined frequencies uniformly distributed over a sampling frequency interval into complex frequency coefficients so that magnitude and phase information at each frequency is immediately available to produce a modulated complex lapped transform (MCLT). The present invention includes a MCLT processor, an acoustic echo cancellation device and a noise reducer integrated with an encoder / decoder device.

A method of modulating communications signals, such as optical fiber, wired electronic, or wireless signals in a manner that facilitates automatic correction for the signal distortion effects of echoes and frequency shifts, while still allowing high rates of data transmission. Data symbols intended for transmission are distributed into N×N matrices, and used to weigh or modulate a family of cyclically time shifted and cyclically frequency shifted waveforms. Although these waveforms may then be distorted during transmission, their basic cyclic time and frequency repeating structure facilitates use of improved receivers with deconvolution devices that can utilize the repeating patterns to correct for these distortions. The various waveforms may be sent in N time blocks at various time spacing and frequency spacing combinations in a manner that can allow interleaving of blocks from different transmitters. Applications to channel sounding / characterization, system optimization, and also radar are also discussed.

An apparatus for determining a room dimension estimate comprises a receiver (101) providing an acoustic room response e.g. generated from acoustic measurements. A peak detector (103) detects a set of peaks in the acoustic room response in a frequency interval having an upper frequency of no more than 400 Hz. A store (107) comprises a set of peak profiles with associated room dimension data, and an estimator (105) determines the room dimension estimate from the associated room dimension data and a comparison of the set of peaks to the peak profiles. The estimator may perform the steps of first finding a matching peak profile for the set of peaks from the set of peak profiles; extracting first room dimension data associated with the matching peak profile(s) from the store; and determining the room dimension estimate in response to the first room dimension data. The peak profiles may represent calculated Eigenfrequencies.

An enhanced NodeB (eNB), user equipment (UE) and method of Channel State Information (CSI) measurement and reporting using reduced bandwidth are generally described herein. The UE is preconfigured with a resource configuration information or the configuration information is transmitted to the UE from the eNB. The configuration information indicates a narrowband region on which to monitor for and receive physical downlink control and data channels and perform measurements for CSI computation. The region has a reduced bandwidth that is supported by the UE and is free from subbands outside of the region. The UE takes measurements of downlink transmissions using the assigned resources. The measurements are limited to subbands included within the region. The UE calculates the CSI based on an unrestricted time interval within subframes of the region and a restricted frequency interval free from physical resource blocks outside the region. The UE reports a region-specific wideband CSI that includes at least a region-specific wideband Channel Quality Indicator to the eNB.

What is disclosed is a system and method for recovering a patient's cardiac pulse rate from a sequence of video images recording of that patient. In one embodiment, a reference signal of a particular frequency is generated at predetermined frequency intervals and a constrained source separation is performed on the source data to obtain an estimation of the source signal intended to be recovered. The reference signal is updated and constrained source separation is again performed. These operations are repeated for all frequencies of the reference signal. The frequency at which a minimum error is achieved is determined to be the subject's recovered cardiac pulse frequency. In such a manner, the source signal is extracted and recovered reliably from captured multi-channel RGB signals or multispectral signals. The teachings hereof find their uses in a variety of medical solutions including various military, security and telemedicine applications. Various embodiments are disclosed.

The invention allows for the accurate, real-time readout of the optical frequency of a swept-wavelength laser device by counting the number of fringes of a calibrated etalon that occur as the laser is swept. The distinguishing feature of the present invention is that the etalon fringe signal is phase-locked to a slave signal of a higher multiple frequency. The higher frequency of the slave signal divides the frequency interval of the etalon fringe spacing by the additional frequency multiple. The slave signal therefore generates a scale for optical frequency that is of higher resolution than possible with the etalon alone. The phase-lock also insures that the slave signal tracks monotonic scans of the optical frequency regardless of scan profile.The invention also allows for the precise, real-time control of the optical frequency of a laser during the sweep of the laser. By comparing a signal proportional to the transmission of light through a calibrated Fabry-Perot etalon to a reference control signal, the phase difference between etalon transmission signal and the reference signal may be fed back to the laser to drive the phase difference to zero (phase-lock). The phase-lock ensures that the optical frequency profile of the sweep follows exactly the frequency profile of the reference signal. Tailoring the input reference signal controls the velocity of the optical-frequency sweep.

The present invention relates to a method for selecting operating frequency channels having frequency parameters, such as a frequency interval or at least one carrier frequency, for a network communicating data over a shared medium. The network is configured to communicate within a frequency range, and the frequency range is divided into a plurality of frequency channels f1-fn, each frequency channel defines a predetermined frequency parameter. The data to be communicated over the network is divided into sequences FS, each sequence having a plurality of positions SP1-SPm. The method further comprises regularly scanning the frequency range to identify interfering frequencies generated by interfering networks operating within said shared medium, and assigning a frequency channel fk to each position SPi within the sequences FS based on the identified interfering frequencies, whereby the use of interfering frequencies is limited.

A system which improves wavelength tolerance, compensates dispersion in a simple way, reduces limitation of the fiber input power is disclosed. The operation includes receiving a clock signal from a system clock source; modulating a single mode optical signal based on the clock signal and generating an optical pulse signal having two longitudinal modes, the frequency interval thereof being n×B, n being a natural number and B being a transmission speed; generating a partial response signal by converting a binary NRZ signal from a digital signal source in synchronism with the system clock source; and modulating the optical pulse signal based on the partial response signal, and outputting a binary RZ modulated signal. The binary RZ modulated signal is input into a receiver, where two partial response components in the optical spectra of the input signal are divided, and one or both of the components are received.

A multi-tone photonic oscillator comprises a laser; an optical modulator coupled to the laser; and a delay line and a photodetector coupled to the optical modulator for generating a delayed electrical signal representation of the output of the optical modulator; wherein the optical modulator being responsible for the delayed electrical signal for generating multiple tones where the frequency intervals of the tones is a function of the amount of delay imposed by the delay line.

An Orthogonal Time Frequency Space Modulation (OTFS) modulation scheme that maps data symbols, along with optional pilot symbols, using a symplectic-like transformation such as a 2D Fourier transform and optional scrambling operation, into a complex wave aggregate and be backward compatible with legacy OFDM systems, is described. This wave aggregate may be processed for transmission by selecting portions of the aggregate according to various time and frequency intervals. The output from this process can be used to modulate transmitted waveforms according to various time intervals over a plurality of narrow-band subcarriers, often by using mutually orthogonal subcarrier “tones” or carrier frequencies. The entire wave aggregate may be transmitted over various time intervals. At the receiver, an inverse of this process can be used to both characterize the data channel and to correct the received signals for channel distortions, thus receiving a clear form of the original data symbols.

A rectangle marker on a display of a signal analyzer simultaneously designates time and frequency intervals of data from a signal under test for analysis. The data of the signal under test is displayed as a graph having time and frequency axes. Sub-graphs show data designated by the rectangle marker as processed in the time domain, frequency domain and modulation domain. The resulting display provides an overview of the signal under test and simultaneously provides displays of measurements and analyses for a designated portion of the data.

An encoder for a multi-channel audio signal which comprises a down-mixer (201, 203, 205) for generating a down-mix as a combination of at least a first and second channel signal weighted by respectively a first and second weight with different amplitudes for at least some time-frequency intervals. Furthermore, a circuit (201, 203, 209) generates up-mix parametric data characterizing a relationship between the channel signals as well as characterizing the weights. A circuit generates weight estimates for the encoder weights from the up-mix parametric data; and comprises an up-mixer (407) which recreates the multi channel audio signal by up-mixing the down-mix in response to the up-mix parametric data, the first weight estimate and the second weight estimate. The up-mixing is dependent on the amplitude of at least one of the weight estimate(s).

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:Δ⁢⁢f⁡(V)=c12⁢h⁢1-c12V2Here, c1 is the velocity of wave propagation in the waveguide. This may be found from the asymptotic velocity values of the dispersion curves.

In a multi-radar system, configured comprising a plurality of radar units which generate and output signals the frequency of which increases and decreases periodically, each radar unit generates and outputs signals synchronized with a prescribed sync signal, such that the upper limit and lower limit of the periodically increasing and decreasing frequency is different for the signals of each radar unit, and moreover the timing of the upper limit and lower limit of the signals substantially coincide. By this means, the frequency intervals between signals can be reduced, and more channels can be set, without causing radio wave interference.

A transceiver front-end of a communication device comprises a frequency blocking arrangement, which may be either a transmit frequency blocking arrangement or a receive frequency blocking arrangement. The frequency blocking arrangement has a blocking frequency interval associated with one of a transmit frequency and receive frequency, and a non-blocking frequency interval associated with the other of the transmit frequency and receive frequency. The frequency blocking arrangement is configured to block passage of signals in the blocking frequency interval between said signal transmission and reception node and either said receiver node or said transmitter node. The frequency blocking arrangement comprises a network of passive components comprising at least one transformer and a filter arrangement adapted to have a higher impedance value in the blocking frequency interval than in the non-blocking frequency interval.

A system for processing audio signals comprises a sequence of digital filters each configured to process a selected frequency using a set of coefficients. A filter configured to process a certain frequency shares its coefficients with another filter that processes a frequency that is lower than the first frequency by at least one frequency interval, such as an octave. The first filter samples at a certain sampling rate, and the second filter's sampling rate is determined by multiplying the first sampling rate by the ratio of the second frequency to the first frequency. The filters are evenly grouped into frequency intervals, such as octaves. Filters in an octave are sampled at a sampling frequency that is at least twice as high as the highest frequency processed in that octave.

What is disclosed is a system and method for recovering a patient's cardiac pulse rate from a sequence of video images recording of that patient. In one embodiment, a reference signal of a particular frequency is generated at predetermined frequency intervals and a constrained source separation is performed on the source data to obtain an estimation of the source signal intended to be recovered. The reference signal is updated and constrained source separation is again performed. These operations are repeated for all frequencies of the reference signal. The frequency at which a minimum error is achieved is determined to be the subject's recovered cardiac pulse frequency. In such a manner, the source signal is extracted and recovered reliably from captured multi-channel RGB signals or multispectral signals. The teachings hereof find their uses in a variety of medical solutions including various military, security and telemedicine applications. Various embodiments are disclosed.

Disclosed is an optical time domain reflectometer simultaneously sensing temperature and stress. The system is based on parallel detection of Rayleigh and Brillouin scattered light and includes devices such as a multi-wavelength laser source, a light-pulse modulator, a balance detector, a microwave amplifier, a high-speed data acquisition card, a coupler and a circulator and the like. In the optical time domain reflectometer, the frequency interval of wavelengths of the multi-wavelength laser source is arranged to be in a range of 9-12 GHz, which is equivalent to a frequency shift quantity of Brillouin scattered light in a fiber. A heterodyne coherent detection method is used to carry out parallel detection on Rayleigh and Brillouin scattered spectra and temperature and stress information is demodulated through a Landau-Placzek ratio (LPR) and Brillouin frequency shift distribution; and at the same time, coherent Rayleigh noises are reduced and superposition of the scattered spectra improves the signal-to-noise ratio of the scattered light. The optical time domain reflectometer is capable of realizing simultaneous temperature and stress sensing of a distributed fiber sensing system, improving the signal-to-noise ratio of the scattered light and improving the sensing precision and distance.

A recognition system (10) incorporates a filterbank analyser (16) producing successive data vectors of energy values for twenty-six frequency intervals in a speech signal. A unit (18) compensates for spectral distortion in each vector. Compensated vectors undergo a transformation into feature vectors with twelve dimensions and are matched with hidden Markov model states in a computer (24). Each matched model state has a mean value which is an estimate of the speech feature vector. A match inverter (28) produces an estimate of the speech data vector in frequency space by a pseudo-inverse transformation. It includes information which will be lost in a later transformation to frequency space. The estimated data vector is compared with its associated speech signal data vector, and infinite impulse response filters (44) average their difference with others. Averaged difference vectors so produced are used by the unit (18) in compensation of speech signal data vectors.

A portable electronic device such as a mobile station 22 has a broadcast radio receiver 60 and an internal storage 50 for storing media files 74, 76, 78, 80. When a received broadcast radio signal exceeds a quality parameter, that signal is sent to a speaker 56. Otherwise, the device 22 enters a virtual radio mode and plays the stored media files in an order that is not determined by the user of the device. The order is determined by an instruction stored in the internal storage 50, and switching to the virtual mode is based on a quality of the received broadcast radio signal. Media files may include entertainment music or video files, traffic and weather, DJ commentary, and advertisements. Various media files may be updated on different frequency intervals so that the content remains current, and to better commercialize the invention. Users may add personal media files and may select a genre or source for certain other media files.

The invention discloses a method for designing MIMO radar waveforms. The method mainly solves the problem in the prior art that tolerance of Doppler is poor in the process of waveform design. The implementation steps of the method include the first step of fixing a set of waveform center frequency sequences of a radar and setting an initial phase to be zero, the second step of searching a frequency interval initial variable to find out a frequency interval initial value which satisfies the requirement that the 3dB bandwidth of an emitted energy function equals to the 3dB bandwidth of an ideal emitted energy function, the third step of setting a frequency interval according to the frequency interval initial value, the fourth step of inputting the frequency interval and the initial phase and outputting an emitted energy function difference value, emitting direction sidelobe gain and the sidelobe magnitude of signals after pulse synthesis to construct a cost function, the fifth step of calling the cost function and optimizing the cost function through the minimax method to obtain the frequency interval and the initial phase meeting the requirement, and the sixth step of obtaining a set of final signals according to the frequency interval and the initial phase and completing the design of the waveforms. The waveforms designed through the method have the advantages of being good in the tolerance of the Doppler and applicable to target detection.

A detection method implementing an FMCW waveform is provided, the emitted waveform is formed of a recurring pattern of given period Tr covering an emission frequency band of given width B, each pattern being divided into a given number P of sub-patterns of duration Tr / P covering an excursion frequency band ΔF=B / P, the sub-patterns being mutually spaced by a frequency interval equal to ΔF. The radar performs: a first distance-compression processing operation carrying out a low-resolution distance compression at the scale of each recurring pattern on a fraction B / P of the emission band of width B corresponding to the frequency band covered by each of the sub-patterns; a Doppler processing operation on a given number N of successive recurrences so as to form P ambiguous distance-Doppler maps of low distance resolution, the maps being segmented into various speed domains; a second distance-compression processing operation of resolution that differs depending on the speed domain to which the relative speed of the target with respect to the radar belongs.

Provided is a noise signal suppressing device including: an input unit configured to receive a sound signal; a time / frequency converting unit; an independent peak spectrum extracting unit configured to extract a peak spectrum having independence; a persistence determining unit configured to determine that the peak spectrum having independence persists for a predetermined period or longer; a noise-signal suppressing unit configured to suppress the peak spectrum having independence as the noise signal. The independent peak spectrum extracting unit includes: a first peak extracting unit configured to extract a peak spectrum having higher energy than that of an adjacent frequency signal, and a second peak extracting unit configured to extract a peak spectrum maintaining a frequency interval of equal to or larger than a predetermined value with respect to a peak spectrum adjacent thereto as the peak spectrum having independence.

The invention discloses an air conditioner and a harmonic torque compensation method and control method and device of a compressor. The harmonic torque compensation method comprises the following steps of obtaining a load torque harmonic of the compressor and a motor output electromagnetic torque harmonic of the compressor under any operating condition of the compressor, and determining a harmonic compensation order according to the load torque harmonic and the electromagnetic torque harmonic; obtaining a harmonic frequency corresponding to the harmonic compensation order and determining a harmonic compensation mode according to a frequency interval in which the corresponding harmonic frequency is located; adjusting compensation parameters of the harmonic compensation mode for multiple times according to a default rule and carrying out harmonic torque compensation control on the compressor according to the adjusted compensation parameters in sequence; and determining the final harmonic torque compensation parameters according to the harmonic torque compensation result of the compressor during each operation. Therefore, full-band harmonic torque control of low-order harmonics and high-order harmonics cannot be achieved, and the motor output torque of the compressor better tracks the load torque of the compressor.

A method of making permanent adjustments to the resonant cavity of a laser device in order to match its free spectral range to a specified frequency interval involves monitoring the optical output produced during laser operation or cavity illumination with diagnostic light, determining the free spectral range from the monitored output, and then permanently modifying the effective refractive index of an intracavity waveguide segment of the laser device according to the determined free spectral range obtained from the monitoring step until the desired match is achieved. The permanent index changes can be done in several ways, including illumination of the intracavity segment with an energetic beam (e.g. UV light) to induce a chemical alteration in the waveguide material, such as polymer cross-linking in the waveguide cladding. Evaporative deposition or ablative removal of intracavity waveguide material would also produce the desired permanent modifications.

In an orthogonal frequency division multiplex (OFDM) communication system, data bits are assigned to several carriers to create frequency redundancy in the transmitted waveform. Uniformly spaced carriers occupy the frequency band of the OFDM signal. Multipath nulls caused by reflections of the transmitted signal can occur at periodic frequency intervals, for example in a coaxial cable. A non-periodic pattern of bit allocation to carriers creates frequency diversity that is resistant to periodic multipath nulls existing in the communication channel.