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Showing papers on "Signal published in 2006"


Journal ArticleDOI
TL;DR: Practical examples with artificial current dipoles and interference sources as well as data from real patients demonstrate that the spatiotemporal signal space separation method removes the artefacts without altering the field patterns of the brain signals.
Abstract: Limitations of traditional magnetoencephalography (MEG) exclude some important patient groups from MEG examinations, such as epilepsy patients with a vagus nerve stimulator, patients with magnetic particles on the head or having magnetic dental materials that cause severe movement-related artefact signals. Conventional interference rejection methods are not able to remove the artefacts originating this close to the MEG sensor array. For example, the reference array method is unable to suppress interference generated by sources closer to the sensors than the reference array, about 20-40 cm. The spatiotemporal signal space separation method proposed in this paper recognizes and removes both external interference and the artefacts produced by these nearby sources, even on the scalp. First, the basic separation into brain-related and external interference signals is accomplished with signal space separation based on sensor geometry and Maxwell's equations only. After this, the artefacts from nearby sources are extracted by a simple statistical analysis in the time domain, and projected out. Practical examples with artificial current dipoles and interference sources as well as data from real patients demonstrate that the method removes the artefacts without altering the field patterns of the brain signals.

1,294 citations


Patent
09 Mar 2006
TL;DR: In this paper, the authors proposed to decrease the number of transistors and wires constituting a pixel to increase the aperture ratio, which increases the luminosity obtained from one pixel by increasing the area of a light emitting region in the pixel.
Abstract: When light emitting elements have the same luminance, luminosity obtained from one pixel can be higher as area of a light emitting region in the pixel (also called an aperture ration) is increased. The aperture ratio of a pixel is low if the number of transistors and wires constituting the pixel is large. Thus, the invention is to decrease the number of transistors and wires constituting a pixel to increase the aperture ratio. Instead of a power supply line to which a certain potential is set, a potential supply line which controls a potential by a signal is provided; supplying an applied voltage to a light emitting element can be controlled by a signal of the potential supply line without providing a switch.

1,061 citations


Patent
21 Jun 2006
TL;DR: In this paper, a powered surgical tool with a housing that contains a power generating unit such as a motor is described, where a control module is disposed in a shell that is mounted in the housing.
Abstract: A powered surgical tool with a housing that contains a power generating unit such as a motor. A control module is disposed in a shell that is mounted in the housing. The control module contains a control circuit for regulating the actuation of the power generating unit. The power generating unit emits a signal representative of the operating state of the unit that is transmitted through the structural material forming the shell. Also internal to the control module shell is a sensor that monitors the signal emitted by the power generating unit. This signal output by the sensor is applied to the control circuit. The control circuit, based on the sensor signal regulates actuation of the power generating unit. Wherein the power generating unit is a motor, the signal emitted is the magnetic field that varies with rotor position. The sensor monitors the strength of this field.

924 citations


Journal ArticleDOI
Steven J. Gibbons1, Frode Ringdal1
TL;DR: In this article, a case study of small seismic events at the Barentsburg coal mine on Spitsbergen were detected using the signals from a major rockburst as master waveforms, showing that waveform correlation using a single channel detects signals of approximately 0.7 orders of magnitude lower than is possible using an STA/LTA detector on the array beam.
Abstract: It has long been accepted that occurrences of a known signal are most effectively detected by cross-correlating the incoming data stream with a waveform template. Such matched signal detectors have received very little attention in the field of detection seismology because there are relatively few instances in which the form of an anticipated seismic signal is known a priori. Repeating events in highly confined geographical regions have been observed to produce very similar waveforms and good signals from events at a given site can be exploited to detect subsequent co-located events at lower magnitudes than would be possible using traditional power detectors. Even greater improvement in signal detectability can be achieved using seismic arrays; running correlation coefficients from single sensors can be stacked over an array or network to result in a network correlation coefficient displaying a significant array gain. If two events are co-located, the time separating the corresponding patterns in the wave train as indicated by the cross-correlation function is identical for all seismic stations and this property means that the correlation coefficient traces are coherent even when the waveforms are not. We illustrate the power of array-based waveform correlation using the 1997 August 16 Kara Sea event. The weak event that occurred 4 hr after the main event was barely detected using an STA/LTA detector on the SPITS array but is readily detected by signal matching on a single channel. The main event was also recorded by the far more distant NORSAR array but no conventional detection can be made for the second event. A clear detection is, however, made when the correlation coefficient traces are beamformed over all sensors of the array. We estimate the reduction in detection threshold of a test signal on a regional seismic array using waveform correlation by scaling down a master signal and immersing it into seismic noise. We show that, for this case, waveform correlation using a single channel detects signals of approximately 0.7 orders of magnitude lower than is possible using an STA/LTA detector on the array beam. Waveform matching on the full array provides an additional improvement of approximately 0.4 magnitude units. We describe a case study in which small seismic events at the Barentsburg coal mine on Spitsbergen were detected using the signals from a major rockburst as master waveforms. Many spurious triggers occurred in this study whereby short sections of signal exhibited coincidental similarity with unrelated incoming wave fronts. We demonstrate how such false alarms can almost always be identified and screened out automatically by performing frequency–wavenumber analysis upon the set of individual correlation coefficient traces.

641 citations


Journal ArticleDOI
TL;DR: In this paper, several photonic signal processors, including high-resolution microwave filters, widely tunable filters, arbitrary waveform generators, and fast signal correlators, are discussed, and a new concept for realizing multiple-tap coherence-free processor filters, based on a new frequencyshifting technique, is presented.
Abstract: Photonic signal processing offers the prospect of realizing extremely high multigigahertz sampling frequencies, overcoming inherent electronic limitations. This stems from the intrinsic excellent delay properties of optical delay lines. These processors provide new capabilities for realizing high time-bandwidth operation and high-resolution performance. In-fiber signal processors are inherently compatible with fiber-optic microwave systems and can provide connectivity with built-in signal conditioning. Fundamental principles of photonic signal processing, including sampling, tuning, and noise, are discussed. Structures that can extend the performance of photonic signal processors are presented, including methods for improving the filter shape characteristics of interference mitigation filters, techniques to increase the stopband attenuation of bandpass filters, and methods to achieve large free spectral range. Several photonic signal processors, including high-resolution microwave filters, widely tunable filters, arbitrary waveform generators, and fast signal correlators, are discussed. Techniques to solve the fundamental noise problem in photonic signal processors are described, and coherence-free structures for few-tap notch filters are discussed. Finally, a new concept for realizing multiple-tap coherence-free processor filters, based on a new frequency-shifting technique, is presented. The structure not only eliminates the phase-induced intensity noise limitation, but can also generate a large number of taps to enable the achievement of processors with high performance and high resolution.

639 citations


Journal ArticleDOI
TL;DR: A selection procedure of mother wavelet basis functions applied for denoising of the ECG signal in wavelet domain while retaining the signal peaks close to their full amplitude is presented.

457 citations


Journal ArticleDOI
20 Jan 2006-Sensors
TL;DR: It is shown that the lower bound of the send-on-delta effectiveness is independent of the sampling resolution, and constitutes the built-in feature of the input signal.
Abstract: : The paper addresses the issue of the send-on-delta data collecting strategy to capture information from the environment. Send-on-delta concept is the signal-dependent temporal sampling scheme, where the sampling is triggered if the signal deviates by delta defined as the significant change of its value. It is an attractive scheme for wireless sensor networking due to effective energy consumption. The quantitative evaluations of send-on-delta scheme for a general type continuous-time bandlimited signal are presented in the paper. The bounds on the mean traffic of reports for a given signal, and assumed sampling resolution, are evaluated. Furthermore, the send-on-delta effectiveness, defined as the reduction of the mean rate of reports in comparison to the periodic sampling for a given resolution, is derived. It is shown that the lower bound of the send-on-delta effectiveness (i.e. the guaranteed reduction) is independent of the sampling resolution, and constitutes the built-in feature of the input signal. The calculation of the effectiveness for standard signals, that model the state evolution of dynamic environment in time, is exemplified. Finally, the example of send-on-delta programming is shown.

446 citations


Patent
10 Apr 2006
TL;DR: In this article, a do-it-yourself photo realistic talking head creation system consisting of a template, a handheld device comprising display and video camera having an image output signal of a subject, and a computer having a mixer program for mixing the template and image output signals of the subject into a composite image, and an output signal representational of the composite image.
Abstract: A do-it-yourself photo realistic talking head creation system comprising: a template; handheld device comprising display and video camera having an image output signal of a subject; a computer having a mixer program for mixing the template and image output signal of the subject into a composite image, and an output signal representational of the composite image; a computer adapted to communicate the composite image signal to the display for display to the subject as a composite image; the display and the video camera adapted to allow the video camera to collect the image of the subject, the subject to view the composite image, and the subject to align the image of the subject with the template; storage means having an input for receiving the output signal of the video camera representational of the collected image of the subject and storing the image of the subject substantially aligned with the template.

444 citations


Proceedings ArticleDOI
16 Aug 2006
TL;DR: Gaussian processes can be used to generate a likelihood model for signal strength measurements and parameters of the model, such as signal noise and spatial correlation between measurements, can be learned from data via hyperparameter estimation.
Abstract: Estimating the location of a mobile device or a robot from wireless signal strength has become an area of highly active research. The key problem in this context stems from the complexity of how signals propagate through space, especially in the presence of obstacles such as buildings, walls or people. In this paper we show how Gaussian processes can be used to generate a likelihood model for signal strength measurements. We also show how parameters of the model, such as signal noise and spatial correlation between measurements, can be learned from data via hyperparameter estimation. Experiments using WiFi indoor data and GSM cellphone connectivity demonstrate the superior performance of our approach.

423 citations


Journal Article
TL;DR: The Wigner distribution function of optical signals and systems can be interpreted directly in terms of geometrical optics as mentioned in this paper, which can be applied to partially coherent light as well.
Abstract: The Wigner distribution function of optical signals and systems has been introduced. The concept of such functions is not restricted to deterministic signals, but can be applied to partially coherent light as well. Although derived from Fourier optics, the description of signals and systems by means of Wigner distribution functions can be interpreted directly in terms of geometrical optics: (i) for quadratic-phase signals (and, if complex rays are allowed to appear, for Gaussian signals, too), it leads immediately to the curvature matrix of the signal; (ii) for Luneburg’s first-order system, it directly yields the ray transformation matrix of the system; (iii) for the propagation of quadratic-phase signals through first-order systems, it results in the well-known bilinear transformation of the signal’s curvature matrix. The zeroth-, first-, and second-order moments of the Wigner distribution function have been interpreted in terms of the energy, the center of gravity, and the effective width of the signal, respectively. The propagation of these moments through first-order systems has been derived. Since a Gaussian signal is completely described by its three lowest-order moments, the propagation of such a signal through first-order systems is known as well.

388 citations


Proceedings ArticleDOI
01 Dec 2006
TL;DR: This paper proposes algorithms and hardware to support a new theory of compressive imaging based on a new digital image/video camera that directly acquires random projections of the signal without first collecting the pixels/voxels.
Abstract: Compressive Sensing is an emerging field based on the revelation that a small group of non-adaptive linear projections of a compressible signal contains enough information for reconstruction and processing. In this paper, we propose algorithms and hardware to support a new theory of Compressive Imaging. Our approach is based on a new digital image/video camera that directly acquires random projections of the signal without first collecting the pixels/voxels. Our camera architecture employs a digital micromirror array to perform optical calculations of linear projections of an image onto pseudo-random binary patterns. Its hallmarks include the ability to obtain an image with a single detection element while measuring the image/video fewer times than the number of pixels ? this can significantly reduce the computation required for video acquisition/encoding. Because our system relies on a single photon detector, it can also be adapted to image at wavelengths that are currently impossible with conventional CCD and CMOS imagers. We are currently testing a proto-type design for the camera and include experimental results.

Patent
17 May 2006
TL;DR: In this article, an orientation-sensitive signal output, in which a neutral position of a device is automatically determined in relation to at least a first axis and an angular displacement of the device is measured about at least the first axis, and shaking of the devices is detected.
Abstract: Orientation-sensitive signal output, in which a neutral position of a device is automatically determined in relation to at least a first axis, an angular displacement of the device is measured about at least the first axis, and shaking of the device is detected. A selection of the first control is received, and an output signal is output based at least upon the selection and the angular displacement or based upon detecting the shaking of the device.

Patent
09 Nov 2006
TL;DR: In this article, the authors proposed a communications system comprising a first communications device for receiving data and a wake up signal, which consists of an active mode of operation and a sleep mode for reducing power consumption.
Abstract: The present invention teaches a communications system comprising a first communications device for receiving data and a wake up signal. The first communications device comprises an active mode of operation and a sleep mode of operation for reducing power consumption. Further, the system comprises means for switching the first communications device to and from sleep mode in response to receiving the wake up signal. Further, the system comprises a second communications device for transmitting data to the first device during its active mode, while transmitting the wake up signal to the first device during its sleep mode.

Patent
23 Nov 2006
TL;DR: A power failure detection circuit (4) comprises an input port (5) for applying a voltage signal to be monitored, a voltage rate of change detecting circuit (6-15) connected to said input port, and a first comparator (14-16) for comparing the representative signal to a predetermined limit and for outputting a first power failure signal if said representative signal exceeds the predetermined limit as discussed by the authors.
Abstract: A power failure detection circuit (4) comprises an input port (5) for applying a voltage signal to be monitored; a voltage rate of change detecting circuit (6-15) connected to said input port (5) for deriving a signal representative of a rate of change of said voltage signal, and a first comparator (14-16) for comparing said representative signal to a predetermined limit and for outputting a first power failure signal if said representative signal exceeds a predetermined limit.

Patent
15 May 2006
TL;DR: In this article, a method for communicating information in a digital signal comprising data symbols is disclosed, wherein the information is encoded in a sequence characteristic of pilot symbols distributed amongst the data symbols, such that a receiver is able to determine the sequence characteristic and retrieve the transmitted information.
Abstract: The present invention relates to a communication method, system and signal, and in particular to a method and system for communicating information in a digital signal. It has particular application to satellite or terrestrial packet-based multi-user radio communication systems. A method for communicating information in a digital signal comprising data symbols is disclosed, wherein the information is encoded in a sequence characteristic of pilot symbols distributed amongst the data symbols, such that a receiver is able to determine the sequence characteristic and retrieve the transmitted information. The invention allows information to be encoded into a sequence characteristic of pilot symbols, rather than relying on modulating such information onto the pilot symbols themselves. This allows a significantly larger number of pieces of information to be transmitted than hitherto possible, and the technique is more resistant to large frequency errors than prior techniques.

Patent
Daiki Yagishima1
11 Jul 2006
TL;DR: In this paper, the constant current chopping function and the overcurrent protection function were simultaneously obtained to improve the reliability and safety of a motor drive device, and it was shown that it is possible to simultaneously obtain both functions.
Abstract: A motor drive device ( 1 a ) includes: chopping signal generation means ( 151, 153 ) for generating a chopping signal Sa when drive current of a driver ( 14 ) has reached a first threshold value; chopping signal cut-off means ( 152, 154 ) for cutting off the chopping signal Sa when the drive current has reached a second threshold value which is greater than the first threshold value; and overcurrent protection means ( 16 ) for generating an overcurrent protection signal Se when the drive current has reached a third threshold value which is greater than the first threshold value and its continuation time has reached a predetermined threshold value time. Thus it is possible to simultaneously obtain the constant current chopping function and the overcurrent protection function and to improve its reliability and safety.

Journal ArticleDOI
TL;DR: A novel fast and quiet method of magnetic resonance imaging (MRI) is introduced which creates new opportunities for imaging in medicine and materials science and is expected to be relatively insensitive to sample motion, which is important for imaging live objects.

Journal ArticleDOI
TL;DR: The results demonstrate that HHT is suited for capturing transient events in dynamic systems such as the propagation of structural defects in a rolling bearing, thus providing a viable signal processing tool for machine health monitoring.
Abstract: This paper presents a signal analysis technique for machine health monitoring based on the Hilbert-Huang Transform (HHT). The HHT represents a time-dependent series in a two-dimensional (2-D) time-frequency domain by extracting instantaneous frequency components within the signal through an Empirical Mode Decomposition (EMD) process. The analytical background of the HHT is introduced, based on a synthetic analytic signal, and its effectiveness is experimentally evaluated using vibration signals measured on a test bearing. The results demonstrate that HHT is suited for capturing transient events in dynamic systems such as the propagation of structural defects in a rolling bearing, thus providing a viable signal processing tool for machine health monitoring

Patent
14 Mar 2006
TL;DR: A variable indication estimator as discussed by the authors is an estimator which determines an output value representative of a set of input data, which can reduce input data to estimates of a desired signal, and select a time, and determine output value from the estimates and the time.
Abstract: A variable indication estimator which determines an output value representative of a set of input data. For example, the estimator can reduce input data to estimates of a desired signal, select a time, and determine an output value from the estimates and the time. In one embodiment, the time is selected using one or more adjustable signal confidence parameters determine where along the estimates the output value will be computed. By varying the parameters, the characteristics of the output value are variable. For example, when input signal confidence is low, the parameters are adjusted so that the output value is a smoothed representation of the input signal. When input signal confidence is high, the parameters are adjusted so that the output value has a faster and more accurate response to the input signal.

Journal ArticleDOI
TL;DR: In this article, a 120-GHz-band wireless link that uses millimeter-wave photonic techniques was developed, which achieved error-free transmission of OC-192 and 10-GbE signals over a distance of more than 200 m with a received power of below -30 dBm.
Abstract: A 120-GHz-band wireless link that uses millimeter-wave (MMW) photonic techniques was developed. The output power and noise characteristics of 120-GHz-band MMWs generated by converting a 125-GHz optical subcarrier signal were evaluated. It was then shown that the noise characteristics of the 125-GHz signal generated with these photonic technologies is sufficient for 10-Gb/s data transmission. We constructed a compact 120-GHz-band wireless link system, and evaluated its data transmission characteristics. This system achieved error-free transmission of OC-192 and 10-GbE signals over a distance of more than 200 m with a received power of below -30 dBm.

01 Jan 2006
TL;DR: In this paper, a novel fast and quiet method of magnetic resonance imaging (MRI) is introduced which creates new opportunities for imaging in medicine and materials science, called SWIFT, sweep imaging with Fourier transformation.
Abstract: A novel fast and quiet method of magnetic resonance imaging (MRI) is introduced which creates new opportunities for imaging in medicine and materials science. The method is called SWIFT, sweep imaging with Fourier transformation. In SWIFT, time-domain signals are acquired in a time-shared manner during a swept radiofrequency excitation of the nuclear spins. With negligible time between excitation and signal acquisition, new possibilities exist for imaging objects consisting of spins with extremely fast transverse relaxation rates, such as macromolecules, semi-solids, and quadrupolar nuclei. The field gradient used for spatial-encoding is not pulsed on and off, but rather is stepped in orientation in an incremental manner, which results in low acoustic noise. This unique acquisition method is expected to be relatively insensitive to sample motion, which is important for imaging live objects. Additionally, the frequency-swept excitation distributes the signal energy in time and thus dynamic range requirements for proper signal digitization are reduced compared with conventional MRI. For demonstration, images of a plastic object and cortical bone are shown.

Proceedings ArticleDOI
01 Dec 2006
TL;DR: A framework for analog-to-information conversion that enables sub-Nyquist acquisition and processing of wideband signals that are sparse in a local Fourier representation is developed and an efficient information recovery algorithm is developed to compute the spectrogram of the signal, which is dubbed the sparsogram.
Abstract: We develop a framework for analog-to-information conversion that enables sub-Nyquist acquisition and processing of wideband signals that are sparse in a local Fourier representation The first component of the framework is a random sampling system that can be implemented in practical hardware The second is an efficient information recovery algorithm to compute the spectrogram of the signal, which we dub the sparsogram A simulated acquisition of a frequency hopping signal operates at 33times sub-Nyquist average sampling rate with little degradation in signal quality

Proceedings ArticleDOI
19 Jun 2006
TL;DR: This paper proposes a novel and automated location determination method called ARIADNE, using a two dimensional construction floor plan and only a single actual signal strength measurement, which generates an estimated signal strength map comparable to those generated manually by actual measurements.
Abstract: Location determination of mobile users within a building has attracted much attention lately due to its many applications in mobile networking including network intrusion detection problems. However, it is challenging due to the complexities of the indoor radio propagation characteristics exacerbated by the mobility of the user. A common practice is to mechanically generate a table showing the radio signal strength at different known locations in the building. A mobile user's location at an arbitrary point in the building is determined by measuring the signal strength at the location in question and determining the location by referring to the above table using a LMSE (least mean square error) criterion. Obviously, this is a very tedious and time consuming task. This paper proposes a novel and automated location determination method called ARIADNE. Using a two dimensional construction floor plan and only a single actual signal strength measurement, ARIADNE generates an estimated signal strength map comparable to those generated manually by actual measurements. Given the signal measurements for a mobile, a proposed clustering algorithm searches that signal strength map to determine the current mobile's location. The results from ARIADNE are comparable and may even be superior to those from existing localization schemes.

Patent
29 Sep 2006
TL;DR: In this article, a method, apparatus and arrangement can be provided for obtaining information associated with a sample such as a portion of an anatomical structure, where information can be generated using first data, which can be based on a signal obtained from a location on the sample, and second data can be obtained by combining a second signal received from the sample with a third reference signal.
Abstract: Exemplary method, apparatus and arrangement can be provided for obtaining information associated with a sample such as a portion of an anatomical structure. The information can be generated using first data, which can be based on a signal obtained from a location on the sample, and second data, where the second data can be obtained by combining a second signal received from the sample with a third reference signal. An image of a portion of the sample can also be generated based on the information. For example, the first data can be associated with spectral encoding microscopy data, and the second data can be associated with optical coherence tomography data.

Patent
01 Mar 2006
TL;DR: A physiological measurement system has a sensor, a processor, a communications link and information elements as mentioned in this paper, which is configured to transmit light having a plurality of wavelengths into a tissue site and to generate a sensor signal responsive to the transmitted light after tissue attenuation.
Abstract: A physiological measurement system has a sensor, a processor, a communications link and information elements. The sensor is configured to transmit light having a plurality of wavelengths into a tissue site and to generate a sensor signal responsive to the transmitted light after tissue attenuation. The attenuated light can be used by the system to determine a plurality of physiological measurements. The processor is configured to operate on the sensor signal so as to derive at least one physiological parameter after which of the plurality of physiological measurements the system is configured to or capable of measuring.

Journal ArticleDOI
TL;DR: This paper deals with the demodulation of the current signal of an induction motor driving a multistage gearbox for its fault detection.
Abstract: Demodulation of vibration signal to detect faults in machinery has been a prominent prevalent technique that is discussed by a number of authors. This paper deals with the demodulation of the current signal of an induction motor driving a multistage gearbox for its fault detection. This multistage gearbox has three gear ratios, and thus, three rotating shafts and their corresponding gear mesh frequencies (GMFs). The gearbox is loaded electrically by a generator feeding an electrical resistance bank. Amplitude demodulation and frequency demodulation are applied to the current drawn by the induction motor for detecting the rotating shaft frequencies and GMFs, respectively. Discrete wavelet transform is applied to the demodulated current signal for denoising and removing the intervening neighboring features. Spectrum of a particular level, which comprises the GMFs, is used for gear fault detection


Patent
21 Jul 2006
TL;DR: In this paper, a method for improving the quality of a speech signal extracted from a noisy acoustic environment is provided, where a signal separation process (180) is associated with a voice activity detector (185).
Abstract: A method for improving the quality of a speech signal extracted from a noisy acoustic environment is provided. In one approach, a signal separation process (180) is associated with a voice activity detector (185). The voice activity detector (185) is a two-channel (178,182) detector, which enables a particularly robust and accurate detection of voice activity. When a speech is detected, the voice activity detector generates a control signal (411). The control signal (411) is used to activate, adjust, or control signal separation processes or post -processing operations (195) to improve the quality of the resulting speech signal. In another approach, a signal separation process (180) is provided as a learning stage (752) and an output stage (756). The learning stage (752) aggressively adjus to current acoustic conditions and passes coefficients to the output stage (756). The output stage (756) adapts more slowly and generates a speech-content signal (181,770) and a noise dominant signal (407,773). When the learning stage (752) becomes unstable only the learning stage (752) is reset, allowing the output stage (756) to continue outputting a high quality speech signal.

Journal ArticleDOI
TL;DR: The theoretical arguments for the advantage of the technique, termed phase-rectified signal averaging (PRSA), over conventional spectral analysis are given and it is shown in a numerical test that the threshold intensity for the detection of additional quasi-periodic components is approximately 75% lower with PRSA.
Abstract: We present an efficient technique for the study of quasi-periodic oscillations in noisy, non-stationary signals, which allows the assessment of system dynamics despite phase resetting and noise. It is based on the definition of anchor points in the signal (in the simplest case increases or decreases of the signal) which are used to align (i.e., phase-rectify) the oscillatory fluctuations followed by an averaging of the surroundings of the anchor points. We give theoretical arguments for the advantage of the technique, termed phase-rectified signal averaging (PRSA), over conventional spectral analysis and show in a numerical test using surrogate heartbeat data that the threshold intensity for the detection of additional quasi-periodic components is approximately 75% lower with PRSA. With the use of different anchor point criteria PRSA is capable of separately analysing quasi-periodicities that occur during increasing or decreasing parts of the signal. We point to a variety of applications in the analysis of medical, biological, and geophysical data containing quasi-periodicities besides non-stationarities and 1 / f noise.

Patent
Ahmadreza Rofougaran1
10 Mar 2006
TL;DR: In this article, a beamforming radio frequency (RF) circuit includes a plurality of antennas, an adjust module, and a multiplicity of amplifiers, and the adjust module is operably coupled to interrelate coordinates of a signal with the plurality of adjusted signal components.
Abstract: A beamforming radio frequency (RF) circuit includes a plurality of antennas, a plurality of amplifiers and an adjust module. The plurality of antennas is operably coupled to interrelate a plurality of beamformed signal components with a beamformed signal. The plurality of amplifiers is operably coupled to interrelate the plurality of beamformed signal components with a plurality of adjusted signal components. The adjust module is operably coupled to interrelate coordinates of a signal with the plurality of adjusted signal components.