702 results about "Frequency spectrum analysis" patented technology

A system, method and software for determining a position of a source of a radio emission. Receive signal strength data associated with reception of radio emissions is generated at each of a plurality of radio sensor devices that are at corresponding known positions in an area where the radio emissions are occurring. Using characteristics associated with reception of the radio emissions at each of the sensor devices, the receive signal strength data generated by each of the sensors is matched as corresponding to a radio emission from the same source. The characteristics used to match receive signal strength data may include spectrum analysis data and/or timing analysis data. Once the receive signal strength data is matched, position computations may be performed on the appropriate set of receive signal strength data to compute the position of the source of the radio emission.

A method useful for evaluating abnormal body tremors wherein a subject is positioned onto a support surface and one or more components of the load exerted by the subject upon the support surface are measured. Simultaneously, the cardiac activity of the subject is also recorded and the time interval between each consecutive heartbeat is computed. The measured load output is modified to normalize the weight of the subject and then plotted against a modified frequency wherein each time interval between heartbeats represent a unit of time and a selected equal number of force measurement samples are interpolated between each heartbeat. The frequency spectrum analysis of such a modified power spectrum graph yields information about body tremor which can be compared to a prior analysis of the same subject or to the same analysis of a standard. The standard is created using the identical method upon, preferably, a sufficient number of subjects known to be free of abnormal body tremor to yield an average measure useful for comparison and diagnostic purposes.

A system and method for identifying minor echoes present in an input signal in the situation where a set of major echoes has already been identified from the input signal. The method includes: computing a spectrum F corresponding to a sum of the major echoes; computing a weighted power spectrum S_M of the spectrum F; subtracting the weighted power spectrum S_M from a weighted power spectrum P_IN of the input signal to obtain a difference spectrum; performing a stabilized division of the difference spectrum by a conjugate of the spectrum F to obtain an intermediate spectrum; computing an inverse transform of the intermediate spectrum to obtain a time-domain signal; and estimating parameters one or more of the minor echoes from the time-domain signal. The echo parameters are usable to remove at least of portion of the one or more estimated minor echoes from the input signal.

An intrusion detection system comprises a plurality of sensors (2A . . . 2X) and a corresponding plurality of receivers (3A. . . 3X). Each receiver receives, via the associated sensor, radio frequency signals comprising a multiplicity of transmissions at different frequencies within a predetermined frequency spectrum. The receiver detects the radio frequency signals and computes, for each of a plurality of successive time intervals and for each of the transmission frequencies, a measurement of signal amplitude over the time interval; compares such signal amplitude measurement with at least one threshold and, if the amplitude exceeds the threshold for a predetermined time period, generates a potential alarm signal. A processor (4) compares potential alarm signals from a plurality of sensors and determines that an intrusion has occurred if the potential alarm signal for a particular station does not coincide with a potential alarm signal for a neighboring sensor. Each receiver may output an intruder alarm signal when potential alarm signals occur simultaneously for more than a preset number of a multiplicity of the transmission frequencies.

A voice activity detector that detects talkspurts in a given signal at a high accuracy, so as to improve the quality of voice communication. A frequency spectrum calculator calculates frequency spectrum of a given input signal. A flatness evaluator evaluates the flatness of this power spectrum by, for example, calculating the average of power spectral components and then adding up the differences between those components and the average. The resultant sum of differences, in this case, is used as a flatness factor of the spectrum. A voice/noise discriminator determines whether the input signal contains a talkspurt or not, by comparing the flatness factor of the frequency spectrum with a predetermined threshold.

A system for monitoring reverse paths of a bi-directional cable communication network such as a CATV network, to detect and analyze ingress signals entering a reverse path and ending at a network sub-headend or headend through a corresponding one of communication lines, comprises a plurality of radio frequency signal detectors connected thereto. The radio frequency signal detectors are provided with bandpass filter for receiving a radio frequency signal within the frequency band used, to generate corresponding output signals indicative of the strength of the received radio frequency signal. The output signal generated by the frequency signal detector which is coupled to the communication line corresponding to the ingress signal carrying path is indicative of the strength of the received ingress signal with received reverse signals. The system further comprises a signal processor for analyzing the detector output signals through comparison with one or more predetermined ingress thresholds to generate an alarm signal whenever the ingress signal is detected. The system further comprises a control computer receiving the alarm signal to generate monitoring sequence control data indicative of the communication line corresponding to the ingress signal carrying path to be monitored. The system also comprises a selector switch having a plurality of inputs being connected to the communication lines and being responsive to the monitoring sequence control data to select the input connected to the communication line to be monitored, and signal monitoring instrumentation such as a spectrum analyzer and a broadband analyzer coupled to an output of the switching device and being responsive to the monitoring sequence control data for analyzing the ingress signal and generating alarm message data accordingly. The control computer receives the alarm message data to further generate diagnostic sequence control data for the monitoring instrumentation also used to determine source characteristics of the ingress signal.

A PIM measurement circuit enables making forward and reverse PIM measurements on any 1 port (reflection) or 2 port (transmission) device with the ability to determine in distance where individual PIM impairments are located as well as their magnitude. The PIM measurement circuit includes two frequency sources that are provided through a combiner for a CW characterization of the PIM circuit. To enable distance determination, an FM measurement is created by using a saw tooth offset sweep generator attached to one of the two frequency sources. With downconversion and processing of signals from the PIM impairments, the FM signal provides a frequency variation that is converted using a Fourier transform or spectrum analysis for separation of frequencies, enabling determination of the distance of the PIM sources as well as their magnitudes.

The invention relates to a low voltage power line broadband carrier communication network fault diagnostic device used on site, relates to a corresponding method, and belongs to the carrier communication technical field. The device includes a carrier transmitting and receiving circuit, a communication circuit, a storage circuit, a human-computer interaction circuit, and a microprocessor. The microprocessor comprises a collection unit, a judgment unit, a data frame unit, a monitoring unit, an analysis unit, a topology unit, a positioning unit, a measurement module, a detection module, a frequency spectrum module, a discrimination module, a test module, and an output module. Through the collection and frequency spectrum analysis of noise signals on the power line, various kinds of noise such as background noise, periodic noise, and sudden noise which influence the carrier communication can be intuitively displayed, and various kinds of fault information of the on-site broadband carrier communication network can be fast diagnosed and intuitively reflected, so that corresponding processing measures are timely adopted. The low voltage power line broadband carrier communication network fault diagnostic device and method are suitable for the operation management based on the power line carrier communication network very much.

The invention provides an unmanned aerial vehicle signal processing device and a processing method thereof. The device comprises a receiving module (1), a monitoring module (2), an early warning module (3), an interference module (4) and a transmitting module (5). The early warning module (3) comprises a storage unit (10) which stores unmanned aerial vehicle frequency domain data and a comparison unit (11) which compares current frequency domain data transmitted by a frequency spectrum analysis unit (9) with the unmanned aerial vehicle frequency domain data stored in the storage unit (10). The early warning module (3) alarms when the comparison result is in the preset range. The interference module (4) comprises a baseband signal generator (12) which sets baseband signal frequency, an interference modulator (13) which modulates a baseband signal into a noise signal, a working amplifier (14) which increases noise power and a combiner (15) which combines different noise frequency bands. Close-up flight of an unmanned aerial vehicle can be warned in advance by detecting working frequency range of the unmanned aerial vehicle, and close-up flight of the unmanned aerial vehicle to the protected security area can be prevented.

A hearing device is adapted to be arranged on or at least partly implanted in an individual's head and comprises: an input unit providing an input audio signal; a signal processing circuit adapted to process the input audio signal; an output unit adapted to provide an audible signal to the individual; one or more electrodes adapted to detect electric brain potentials of the individual; and a brainwave measurement circuit adapted to determine one or more EEG signals from electric signals received from the one or more electrodes. The hearing device further comprises: a first spectrum analyser determining first audio spectra; a reconstructor adapted to repeatedly reconstruct second audio spectra; a first correlator to determine coherence between the first and the second audio spectra; and a control unit adapted to alter said processing in dependence on the coherence.

The invention discloses a method for designing a cognitive high-speed wireless communication system under a discrete spectrum condition, and particularly discloses a cognitive high-speed wireless communication system and method under a discrete spectrum condition. The system comprises an authorized frequency band analysis module, an unauthorized frequency band analysis module and a data modulating module, wherein the authorized frequency band analysis module is used for performing frequency spectrum analysis on authorized frequency bands of a communication system to obtain a first available frequency band; the unauthorized frequency band analysis module is used for analyzing other frequency bands of the communication system except the authorized frequency bands or the authorized frequency bands of at least one other system different from the communication system to obtain a second available frequency band; and the data modulating module is used for modulating data to be transmitted in an OFDM/OFDMA (Orthogonal Frequency Division Multiplexing/Orthogonal Frequency Division Multiple Access) mode based on the first available frequency band and the second available frequency band.

The invention concretely discloses a wide area measurement system which is applied to a phasor measurement unit and based on local frequency spectrum analysis, which comprises a WAMS main station, a PMU substation and a power data network; the PMU substation comprises a GPS time service unit, a synchronized phasor acquisition unit, and a data centralized processing unit; the WAMS main station sends measurement and configuration information, measurement information to be detected and thresholds of a plurality of low-frequency oscillation parameters and receives the parameters measured by low-frequency oscillation which exceed the thresholds and return from each PMU substation for comprehensive analysis in order to obtain overall oscillation mode information; the PMU substation also comprises a frequency spectrum analysis unit and a low-frequency oscillation detection unit. The invention also discloses a phasor measurement unit based on the local frequency spectrum analysis. The adoption of the system and device of the invention can realize real-time and rapid low-frequency oscillation detection and analysis of a large-scale electricity grid.

The invention relates to the precision shaft angle measuring instrument precision detection filed, more particularly to an angle measurement precision detection apparatus of an encoder and a detection method thereof. The apparatus comprises a coupling assembly, a precision main shaft, a motor, a precision encoder, a connection base, a rotary table, a workbench, and a computer system. The precision encoder is employed as a reference and is connected with the precision main shaft coaxially. The precision main shaft is driven by the motor; and an output shaft of the precision main shaft is connected with a detected encoder. The computer controls the rotating speed and the position of the motor as well as simultaneously collects angle measurement data of the precision encoder and the detected encoder; and an error value representing deviation of the position output of the detected encoder from the position output of a reference precision encoder is obtained in rotation angles from 0 degree to 360 degrees of the precision main shaft. And processing is carried out by the computer to provide various measurement errors of the detected encoder and error frequency spectrums. According to the invention, beneficial effects are as follows: there are lots of measurement points and measurement can be carried out continuously, so that various errors of a detected encoder can be reflected; a frequency spectrum analysis on an error source can be carried out; automatic measurement is carried out, the measuring period is short and efficiency is high; and electronization of data processing is realized as well as detection data are filed.

Methods for recovering a detected signal in non-contact vital sign detection are provided. According to one embodiment, a detected reflected signal from a non-contact vital sign detection system can be received and provided along I channel and Q channel signal lines. A complex signal S(t) can then be reconstructed from the I channel and Q channel signal lines through complex signal demodulation. A Fourier transform can be used to obtain the detected signal's spectrum for spectrum analysis. Angular demodulation can be used to recover the information corresponding to original body movement. The complex signal demodulation and angular demodulation techniques used to provide information to determine original body movement are capable of avoiding the null detection point without limitations on frequency tuning or channel selection.

The invention relates to a method for diagnosing faults of a planetary gear system of a wind driven generator under variable rotating speed. The method for diagnosing the faults of the planetary gear system of the wind driven generator under the variable rotating speed aims to overcome defects in a method for diagnosing variable rotating speed faults in the prior art. According to the method for diagnosing the faults of the planetary gear system of the wind driven generator under the variable rotating speed, a method that order data envelopment analysis is carried out on signals is adopted, namely, input (output) shaft rotating speed signals n(t) are obtained through a rotating speed sensor, then a fitting function (please see the formula in the specification) is obtained through fitting, a function (please see the formula in the specification) of changes of rotating angles along with time is obtained through integration, a time sequence tk of equal angle resampling is obtained through an interpolation method, interpolation is carried out on accelerated speed vibration signals Y(t) through the time sequence tk to obtain equal angle resampling signals (please see the symbol in the specification), then FTP is carried out on the envelop of the equal angle resampling signals (please see the symbol in the specification), and thus an order envelop spectrum can be obtained. The problem brought by the variable rotating speed can be well solved through the order analysis, interference of noise can be well restrained through envelop analysis, and thus the order envelop method can be well applied to fault diagnosis of the planetary gear system of the wind driven generator.

This invention relates to test to the passive intermodulation performance of the communication system, which controls an emitter to emit test signals according to a preset mode, controls a receiver to scan and receive the signals in the test bands and analyze spectrums of the received signals to evaluate the entire passive intermodulation performance of the base station, in which, the original outside interference signals are received at the shut-off state of the emitter to eliminate its influence and measure the performance accurately and the received test bands are computed accurately by the known carrier frequency sphere, intermodulation stages and the received frequency sphere parameters and the test signal receiving quality is increased by scanning the emitted and received continuous waves.

A transmitter for transmitting signals to targets and a receiver for receiving signals reflected from targets are included. The transmitter outputs CW signals for detecting direction and velocity of the target. The receiver performs: a function of receiving signals reflected from targets with a plurality of receiving antennas at the same time as transmitting from the transmitter, and performing spectral analysis with respect to receiving signals to thereby classify them by velocity component; a function of correlating signals of the receiving antenna systems; a function of integrating the signals correlation-processed; and a function of obtaining phase fronts of signals made incident on an antenna face from the phase differences of signals between receiving antennas, and performing two-dimensional FFT to the outputs to thereby measure the direction and velocity of the target.

The invention provides a pre-stack seismic data frequency band expanding method of combining well information and horizon information. The pre-stack seismic data frequency band expanding method comprises steps that signal-to-noise ratio spectrum analysis, spectral analysis, and band division scanning of seismic data are carried out to determine a dominant frequency band and to-be-compensated frequency bands; correction and well-seismic matching of well logging data are carried out to construct a well-side expected seismic record; by using a well point reflection coefficient, a well-side seismic record, and a horizon interpretation data, a sparse reflection coefficient section is constructed, and then expected seismic records of non-well points are acquired; by adopting an original seismic record and a reversed wavelet convolution, the expected seismic record is approached, and a corresponding bilateral reversed wavelet is acquired; a frequency-expanding operator acquired by a stacked record is used for a CRP trace gather, and the frequency-expanding operator is used to process every data of the CRP trace gather to acquire the high frequency frequency-expanding record and the low frequency frequency-expanding record of the CRP trace gather; the data reconstruction of the low frequency data acquired by the frequency expansion, the original dominant frequency band, and the high frequency data acquired by the frequency expansion is carried out to acquire wide frequency band seismic data.

The invention relates to a vibration stress relief method using an electric vibration experimental system and a device thereof. The method comprises the following steps: residual stress in a workpiece is measured, and dynamic stress level applied during vibration stress relief for the workpiece is determined; frequency spectrum analysis for the workpiece is carried out by an electric vibration table to preferably choose a plurality of harmonic frequencies; the exciting force of sinusoidal fixed-frequency or frequency sweep is randomly applied on the workpiece, the dynamic stress level of the workpiece is detected in real time in the process of force application, and proper exciting force is chosen according to parameters adjusting the exciting force of vibration table; under proper exciting force, continuous ageing treatment for the workpiece is carried out till the operation is finished after reaching the set time. The device comprises the electric vibration table, a dynamic stress measuring system and a vibration controller. The invention has simple technique and low operation cost, and is suitable for workpieces with different sizes; the process is high-efficient and fast, and saves energy and protects environment; furthermore, the device has simple structure and convenient operation, small occupying space and low energy consumption, and is widely applied to the technical field of machining.