Abstract: The application describes method and apparatus for amplification. An amplifier circuit (300) is described for driving a load (101) connected between first and second output nodes (103p, 103n) based on an input signal (Sin). The amplifier circuit includes first and second signal paths for generating respective first and second driving signals (Soutp and Soutn) at the first and second output nodes, each of the first and second signal paths comprising a respective sigma-delta modulator (301p, 301n). A correlation controller (302) is configured to control the first and second signal paths to provide correlation between at least some noise components of the first and second driving signals.

Abstract: A method for estimating a property of a signal (1) sensed in an electrical system, comprises the steps of sensing the signal (1) and estimating a fundamental period of a fundamental of the signal (1) by comparing the sensed signal (1) with at least one threshold (2) to detect threshold crossings and estimating the fundamental period from the threshold crossings. The signal property is then estimated from the fundamental period and/or from the sensed signal (1) during an interval of a length of the fundamental period. An electronic device according to the invention comprises a micro controller and/or an analogue circuitry which performs the method for estimating a property of a signal. Preferably, the micro controller and/or analogue circuitry controls other parts of the electronic device depending on the results obtained by the method for estimating a property of a signal.

Abstract: A method, computer program product, and computer system for receiving, by a computing device, an input signal. A first power spectral density estimate may be generated for a linear reverberant component associated with the input signal. A second power spectral density estimate may be generated for a non-linear reverberant component associated with the input signal. A power spectral density estimate may be generated by combining the first power spectral density estimate for the linear reverberant component and the second power spectral density estimate for the non-linear reverberant component. One or more parameters for at least one of the linear reverberant component and the non-linear reverberant component may be updated. One or more undesired signal components in an output signal resulting from the input signal may be reduced via residual echo suppression based upon, at least in part, updating the one or more parameters.

Abstract: Systems, methods and devices are disclosed for directing and focusing signals to the brain for neuromodulation and for directing and focusing signals or other energy from the brain for measurement, heat transfer and imaging. An aperture in the skull and/or a channel device implantable in the skull can be used to facilitate direction and focusing. Treatment and diagnosis of multiple neurological conditions may be facilitated with the disclosed systems, methods and devices.

Abstract: In accordance with embodiments of the present disclosure, a processing system may include multiple selectable processing paths for processing an analog signal in order to reduce noise and increase dynamic range. Techniques are employed to transition between processing paths and calibrate operational parameters of the two paths in order to reduce or eliminate artifacts caused by switching between processing paths.

Abstract: Diversity combining schemes have been extensively used in wireless and free space optical communication systems. The present invention of a system and method for free space optical communications where multiple gain combiner (MGC) provides a better performance as compared to selection combining (SC) and equal gain combining (EGC) and can also be used for wireless applications. It also gives a cost effective solution with a minimal degradation in quality when maximal ratio combining (MRC) is compared in terms of hardware complexity and implementation cost. There is no need for present channel state information. Also, Adaptive weight adjustment is not required in present invention. Therefore, the MGC of system and method disclosed in the present invention is a simple, cost effective and high performance diversity combiner.

Abstract: A method and a system for measuring an audio transmission delay are provided. Synchronization operation is performed on transmission of an original audio codebook to be tested between a transmitter and a receiver. A transmitter starts sending the original audio codebook to be tested to a receiver in response to sending start instruction information, and stops sending the original audio codebook to the receiver in response to sending end instruction information. The receiver starts capturing the original audio codebook from the transmitter in response to receiving start instruction information and stops capturing the original audio codebook from the transmitter in response to receiving end instruction information. The audio transmission delay is obtained based on a test audio codebook captured by the receiver and the original audio codebook pre-stored in the receiver.

Abstract: Systems and methods are disclosed for removing nano-particulates from a gas. The systems may include a chamber to contain the particulate-containing gas, a source of the gas, a source of water vapor, a source of a supersonic gas, and at least one ultrasonic transducer in contact with the chamber. The chamber may also include one or more receptacles to receive the particulates. The methods may include introducing the particulate-containing gas and the water vapor into the chamber. A gas may be introduced into the chamber at supersonic speeds thereby cooling the water vapor to form nucleating ice crystals. The ultrasonic transducers may then introduce ultrasonic power into the chamber thereby causing the particulates to contact the ice crystals. The nucleating crystals, with their attached particulates, may then fall under gravity to be captured in the receptacles.

Abstract: A conformal antenna system comprising one or more proximate antenna elements for very reliable localized reception and transmission of radiowave energy and power particularly in frequency controlled VHF, UHF and microwave spectrum is described. The system incorporates effective angle or proximity dependent interference mitigation for conventional transmitters/receivers or master controlled constellations of wireless devices, and is suitable for temporary or permanent installation and use in a variety of outdoor and in-building locations. The antenna elements are configured and optimized for close proximity but unobtrusive positioning near the point of use on stages, in concert halls, movie studios, houses-of-worship, and convention centers, and are configured to be relatively unaffected by people or furniture in very close proximity. Methods for manufacturing and using close proximity antennas are disclosed, as are systems and methods for the generation and control of signals thereto.

Abstract: Methods and systems for estimating arrival time of switching events include measuring two or more emission events from a device under test under different skew conditions. The two or more emission events are close in time and space when no skew condition is applied. The measured waveforms of the two or more emission events are analyzed with associated skew conditions to determine a skew value that corresponds with a time separation between the two or more emission events.

Abstract: In a method for detecting leakage in a digital cable system, at least one first signal is inserted on the cable system. The at least one first signal has an amplitude multiple tens of dB below the digital channel power of the digital channels carried on the cable system. A second signal containing the first signal is received. The second signal is converted to an intermediate frequency (IF) signal. The IF signal is digitized and samples of the digitized IF signal are obtained. Digitized samples of a third signal at the nominal frequency of the first signal at maximum amplitude converted to the IF are provided. The digitized IF signal and the digitized samples of a third signal at the nominal frequency of the first signal at maximum amplitude converted to the IF are correlated. The presence of the inserted first signal is detected based upon the result of the correlation. In another method, a pair of first signals are inserted on the cable system.

Abstract: Various embodiments relate to a method of determining the presence of a spread spectrum signal, including: receiving N input samples of a signal; performing a first autocorrelation on the N input samples with a first offset; performing a second autocorrelation on the N input samples with a second offset; performing a third autocorrelation on the N input samples with a third offset; performing a fourth autocorrelation on the N input samples with a fourth offset; performing a fifth autocorrelation on the N input samples with a fifth offset; determining if the values of the first, second, and third autocorrelations are decreasing, and determining if the values of the fourth and fifth autocorrelations are less than a threshold value, then determining that a spread spectrum signal is present in the N input samples.

Abstract: A search frequency correction method includes: obtaining correlation values by correlating between a received signal that is modulated by direct sequence spread spectrum modulation and a replica code of a spread code with respect to I and Q components at a predetermined search frequency, obtaining accumulated correlation values by accumulating the correlation values of each polarity inversion interval with respect to the I and Q components, calculating a plurality of combinations of the accumulated correlation values in both signs, selecting one of the combinations based on the calculation results of the respective combinations, and correcting the search frequency based on a time variation of an IQ phase represented by the accumulated correlation values of the one of the combinations.

Abstract: A lightning strike simulation apparatus includes a storage device for storing lightning strike data, a setting unit for setting a simulation target in a simulation space, a downward leader advancing unit for advancing a downward leader from a lightning strike start position set by the setting unit, an upward leader advancing unit for advancing upward leaders from lightning strike-receiving candidate points set in the simulation space when a distance between a leading edge of the downward leader and a reference point is within a first threshold value, and a lightning strike point determination unit for, when a distance between a leading edge of the downward leader and a leading edge of any one of the upward leaders is within a second threshold value, determining that the lightning strike-receiving candidate point corresponding to the any one of the upward leaders is a lightning strike point.

Abstract: A method and a device for measuring the phase noise of a signal registers the measurement signal (V) with a given measurement frequency (f1) and with a superimposed phase noise (f1(t)), divides the measurement signal (V) into a first and second measurement signal (V1?, V2?), derives a first signal (V1) with a first frequency ((f1+f1(t))/N) reduced relative to the measurement frequency (f1) and the superimposed phase noise (f1(t)) and a second signal (V2) with a second frequency ((f1+f1(t))/M) reduced relative to the measurement frequency (f1) and the superimposed phase noise (f1(t)), determines a third signal (V3) with a third frequency (f3(t)) compensated by the measurement frequency (f1) relative to the first frequency ((f1+f1(t))/N) of the first signal (V1) and a fourth signal (V4) with a fourth frequency (f4(t)) compensated by the measurement frequency (f1) relative to the second frequency ((f1+f1(t))/M) of the second signal (V2) and determines a correlation spectrum from the third and fourth signal (V3,

Abstract: A coherent integration section synthesizes an IF signal stored in a memory and a C/A code replica generated by a code generation section using a mixer to calculate a correlation value, and integrates the correlation value using an integration section. An integration count monitoring section counts the integration count of the integration section. When a saturation control section has detected saturation of integration of the correlation values, the integration count monitoring section causes the integration section to suspend integration when the integration count is equal to or less than a reference count, and allows the integration section to continue integration when the integration count has exceeded the reference count.

Abstract: An interpolated signal generating circuit (101) generates interpolated signals (SIG1-SIGN) of two consecutive discrete signals (SIG). N measuring circuits (501) measure interpolated signals. Since the interpolated signals are measurement targets, N-times oversampling measurement can also be performed for the discrete signals. With the oversampling measurement, the frequency spectra of the signal components of the discrete signals are maintained, and only the frequency spectrum of a noise component due to a quantization error increases to a high-frequency band, thereby reducing a noise component per unit frequency. Therefore, removing a high-frequency component from a measurement result from each measuring circuit using a low-pass filter (502) makes it possible to improve the signal-to-noise ratio of the measurement result as compared with a case in which no oversampling is performed.

Abstract: A real-time, multi-sensor local-area lightning detection network system. The system uses waveform indicative of electrostatic field changes with respect to time is generated at each of N locations due to a cloud-to-ground lightning strike occurring in the vicinity of the N locations. Each waveform is integrated to generate a corresponding electric field associated with a corresponding one of the locations. A mathematical relationship is used to determine a ground surface location of the lightning strike, height of the lightning strike, and charge per unit length of the lightning strike using each electric field generated during integration of the waveforms.

Abstract: A communications apparatus and method use tapped delay lines as multiplexers and demultiplexers. In one embodiment, a receiver (100) uses a tapped delay line (110) as a demultiplexer to acquire a burst communication at very high data rates in the range of 2.5 to 80 Gbps with low preamble overhead. A sliding window correlator (114) continually samples the delay line (110) to determine when a PN encoded word is contained therein. The transmission frequency is pre-acquired before any data is present through the use of a ring oscillator frequency calibration loop (130) that is imbedded within the tapped delay line (110).

Abstract: A method of measuring relative channel delay between components of a video signal includes removing a local mean from each of the pair of input component signals and cross-correlating the resulting pair of input component signals. A mean is removed from the cross-correlation and a centroid for the cross-correlation is found within a region bound by nearest zero-crossing to a peak in the cross-correlation. The centroid is then converted to a delay time as a function of sample rate after removing a sample offset. Also a normalized peak value of the cross-correlation provides a figure of merit for the probable accuracy of the delay measurement.

Abstract: A signal can be analysed to determine statistical characteristics indicative of, for example, the predictability or time reversibility of the signal. The signal is examined to locate events corresponding to the crossing of predetermined levels with predetermined slopes. Multiple versions of the signal are combined, the versions being shifted with respect to each other by amounts corresponding to the spacings of the detected events. The shape of the resulting representation provides statistical information regarding the signal.

Abstract: A system for the detection of narrowband signals in wideband noise that combines information across two frequency channels that straddle the frequency of the target signal. Two band pass filters having center frequencies that straddle the frequency of the target signal and that have phase transfer functions that differ by 180 degrees relative to each other at the frequency of the target signal. The presence of the target signal is detected by performing a running cross-correlation of the outputs of saturating, non-linearities that follow from the filters, and determining when the output of the running cross-correlator drops below a predetermined threshold due to the phase shift between the two filter responses caused by the presence of the target signal.

Abstract: There are provided frequency analyzing method and apparatus, and a spectrum analyzer capable of reliably detecting and displaying a radio wave even if the radio wave is a frequency spread or low level one. A signal to be measured existing in a frequency band to be measured is extracted by a plurality of measurement signal extracting devices, and each of the extracted plural signals to be measured is frequency analyzed to compute a correlation value with respect to the plural results of frequency analyses. If the computed correlation value is equal to or greater than a preset value, a decision that the signal to be measured exists in the analyzed frequency is rendered, and if the computed correlation value is smaller than the preset value, a decision that the signal to be measured does not exist in the analyzed frequency is rendered. The decision results are displayed.

Abstract: A lightning detection and data acquisition system. A plurality of remote programmable sensor is utilized to detect cloud to ground and IC lightning strikes. Analog representations of the lightning strikes are converted to digital signals. The digital signals are classified according to user changeable criteria. The classified digital signals are compressed and optionally decimated. The compressed information is transmitted to a central location where it is decompressed and used to correlate the location, magnitude, and travel path of the detected lightning strikes.

Abstract: There are provided frequency analyzing method and apparatus, and a spectrum analyzer capable of reliably detecting and displaying a radio wave even if the radio wave is a frequency spread or low level one. A signal to be measured existing in a frequency band to be measured is extracted by a plurality of measurement signal extracting devices, and each of the extracted plural signals to be measured is frequency analyzed to compute a correlation value with respect to the plural results of frequency analyses. If the computed correlation value is equal to or greater than a preset value, a decision that the signal to be measured exists in the analyzed frequency is rendered, and if the computed correlation value is smaller than the preset value, a decision that the signal to be measured does not exist in the analyzed frequency is rendered. The decision results are displayed.

Abstract: A vibration testing device includes a computer system having: a measurement processing block for inputting an output of the monitoring sensor and processing the output; a model substituting block for modeling characteristics of the test piece, calculating a response quantity corresponding to a drive condition of an actuator, and inputting the calculation result to a numerical simulation block and the parameter changing block; the parameter changing block for comparing the calculation result of the model substituting block with the processing result of the measurement processing block, and changing the parameter; the numerical simulation block for calculating a vibration response in accordance with a previously input structure numerical model; and a waveform generating block for calculating a time function of a deformation to be applied to the test piece, and outputting the time block to the actuator controlling device.

Abstract: Analyzing a swept spectrum signal formed by mixing a ramping local oscillator and an input signal to generate an IF signal, the resulting IF signal having a phase change with respect to the input signal, the phase change including a quadratic portion. For analysis, the IF signal is processed such that the quadratic component of the phase change is removed. The quadratic component of the phase change is removed with a complex filter.

Abstract: An optical correlator is used to detect the presence of a target in a laser detection and ranging (LADAR) system by analyzing the return signal, and to provide initial estimates of the targets range and velocity to the LADAR receiver. The optical correlator includes an acoustic optical Bragg cell that deflects an input laser signal using the received and down-converted LADAR signal. An integrating optical detector is disposed to receive the optical outputs of the acoustic optical Bragg cell and an optical processor analyzes and processes the integrating optical detector data. The integrating optical detector integrates the optical outputs of the Bragg cell over time and the integrating optical detector output is sampled over a sampling period so that target detection is uncorrelated to noise.

Abstract: A high resolution cross correlation, coherent integration type spectrum analyzer for use in obtaining detailed spectral signatures of subsurface and surface vessels correlates short discontinuous records of the incoming signal with reference signals of known frequencies and accumulates the results to establish cross correlation over a relatively long total record made up of the short discontinuous record segments, with the long combined record being responsible for the high resolution of the system.

Abstract: Method, apparatus and computer programs are described for compensating for the effect of temperature on the sensitivity of electrostatic ultrasound (US) transducers, particularly as used in an automotive occupancy sensing (AOS) systems for sensing the nature or type of occupant and the location of the occupant with respect to the vehicle interior. The invention permits the AOS to classify the occupancy state of the vehicle from a US echo signal substantially free of the effects of temperature on signal amplitude. A capacitive divider or voltage monitor is employed to measure the capacitance of the transducer. The voltage monitor output is used by the scaling algorithm of a compensator to determine the scaling factor to be applied to the US transducer signal to compensate for the effect of temperature on the transducer sensitivity.

Abstract: Apparatus (15, 30) and methods for performing acoustical measurements are provided having some and preferably all of the following features: (A) the system (15, 30) is operated under near-field conditions; (B) the piezoelement (40) or piezoelements (40, 48) used in the system are (i) mechanically (41, 49) and electrically (13, 16) damped and (ii) efficiently electrically coupled to the signal processing components of the system; (C) each piezoelement (40, 48) used in the system includes an acoustical transformer (42, 50) for coupling the element to a gaseous test medium (9); (D) speed of sound is determined from the time difference between two detections of an acoustical pulse (81, 82) at a receiver (40, FIG. 3; 48, FIG.