Abstract: A method and system for synchronizing the sampling frequency, at which power system data is sampled, with the frequency of the power system. Adjustments to the sampling frequency can be made by comparing first and second derivatives to threshold values.

Abstract: A mechanical signature analysis system for analyzing frequencies and magnitudes of vibrations in an operating test disc drive includes a test data acquisition module connected to the test disc drive to acquire time domain test data and convert it into frequency domain test data, a typical disc drive data module having frequency domain data for a typical disc drive, and a failure analysis module having failure limits associated with the typical disc drive frequency domain data to determine whether the test data are within the failure limits. An output module displays failure analysis results.

Abstract: A built-in auto-tuning system of a motor control system provides an auto-tuning of the motor control system. The built-in tuning system generates and applies a random noise test signal to the controller. In response to the test signals, the tuning system obtains response data such as the gains and phases over a wide range of operating frequencies. Based on the received data, the tuning system generates an open-loop Bode plot of the control system. The tuning system then calculates the phase and gain margins of the control system. The calculated gain and phase margins are compared with a set of predetermined values by the tuning system to automatically adjust the compensation parameters of the motor control system for a stable operation.

Abstract: A method of and system for determining calibration offsets to account for delays introduced “downstream” of the reference driver (24) of a tester system (18) to test electronic components such as SRAM semiconductor memory devices. Such delays are created by, among other elements, receiver channels (30) of the tester system. A plurality of calibration modules (100) are provided, one for each receiver channel. Each calibration modules has a transmission line (110) with a known delay, a first contact 102′ and a second contact 102″. The tester system includes a socket (52) having a plurality of contactors (54) for contacting the reference clock contact and data output contacts of the electronic components undergoing test. The first contact of each calibration module is positioned to engage the contactor that engages the reference clock contact of the electronic component.

Abstract: The present invention concerns a method and a device (1) operating by intepolation in a discrete spectrum to determine characteristics Pq of a signal s(t,Pq). In accordance with the invention, said device (1) includes means (2, 4, 6, 8, 10, 12) for determining said characteristics Pq from a system of m equations: z(fi)=Fi[w(t).s(t,Pq)].h(f), i varying from 1 through m and m being greater than or equal to 2, wherein: z(fi) is an element of a discrete spectrum obtained by Fourier transformation of the signal s(t,Pq), Fi is a discrete Fourier transform, w(t) is a temporal weighting function, and h(f) is a frequency transfer function of an anti-aliasing filter.

Abstract: A test system for measuring a frequency response of a signal path 148 by transmitting a short duration burst test signal 234 from a remote point 152, capturing an impaired burst test signal 432 on a digital signal acquisition unit 416, and analyzing the received signal by digitally processing it with an unimpaired burst test signal 434. A dynamic range test can also be performed with the same burst test signal by removing the energy in a part of the frequency band with a notch filter 232, and then increasing the power of the burst test signal level until non-linear distortion occurs. The distortion products will fill-in the notch, allowing the clipping threshold of the signal path to be measured. A burst trigger signal 244 generated by the transmitter device 201 causes a digital signal acquisition unit to acquire an impaired burst test signal.

Abstract: A measurement device for measuring an internal quality of a fruit or vegetable with light is intended to be able to obtain the internal quality at higher speed and with accuracy. In the measurement device of the internal quality, transmitted light through the fruit or vegetable is split into a plurality of frequency regions and the measurement device is provided with a plurality of processing circuits for carrying out intensity data calculating operations simultaneously and in parallel for the respective frequency regions.

Abstract: The present invention relates to a process for determining harmonic oscillations of a fundamental component of an electrical signal, wherein the signal is sampled with a sampling frequency corresponding to a multiple of the fundamental component's frequency. The sampled values of the signal are subjected, after analog-to-digital conversion, to a discrete Fourier transformation to determine the harmonic oscillations. The sampling is performed with a non-integer multiple of the frequency of the fundamental component and the discrete Fourier transformation is performed while the frequency resolution is increased over several periods of the fundamental component to determine the harmonic oscillations.

Abstract: An electrical circuit having an oscillator and additional structural elements that are connected to the oscillator. In an iterative method, upon variation of circuit parameters of the additional structural elements, the following steps are carried out for each instance of the circuit parameters: a stability analysis of the circuit is carried out for each respective instance, and if the circuit oscillates, a first value is assigned to the instance in a matrix in which all the instances being examined are stored. Otherwise, a second value is assigned to the instance in the matrix.

Abstract: An equivalent circuit and an analysis method are provided for highly accurately indicating characteristic of an inductance element wherein ferrite material is used. An equivalent circuit is used, wherein a closed circuit with resistance Rm1 and Rm2, and inductance Lm1 and Lm2 magnetically connects to inductance Ls of LsCpRp parallel circuit at coupling coefficients k1 and k2. First, the values of circuit constants Ls, Rp, and Cp are determined by making use of the conditions at the resonance point. Next, changes of reactance component in the equivalent circuit for frequency are calculated, based on the determined values of circuit constants Ls, Rp, and Cp, and find the values of frequency fm1 and fm2 whereat reactance component should be decreased by comparing frequency changes of measured reactance component.

Abstract: A method of measuring non-coherent electrical signals using either windowed or non-windowed digital signal processing. The method includes the steps of providing a digitized version of the non-coherent electrical signal; generating a matrix A of correlations between sine and cosine components of known correlation frequencies and sine and cosine components of signal frequencies; generating an inverse matrix A−1 of the correlation matrix; generating a second matrix B of correlations between sine and cosine components of the correlation frequencies and the digitized non-coherent electrical signal; and generation of a third matrix C which represents the measured amplitudes of the sine and cosine components of the non-coherent electrical signal.

Abstract: The present invention provides an oscillation measuring method comprising: a laser beam emission step S1 for emitting a laser beam to an object to be measured; a return beam reception step S2 for receiving a return beam reflected by the object and having an object Doppler frequency according to a velocity of the object; a self-mixing step S3 for mixing the return beam having the Doppler frequency with another beam emitted upon reception of the return beam and generating a self-frequency according to a resonator change during a time from the emission to the reception of the return beam, so as to generate a beat wave containing the object Doppler frequency superposed with the self-frequency; and an oscillation information output step S4 for outputting the beat wave or information obtained from signal processing of the beat wave as the object oscillation information. This enables to measure a fine oscillation of an object to be measured.

Abstract: A method for measuring the ripeness and the texture of a fruit, the method comprising a step for applying a vibration having sequentially hanging frequencies to a fruit to be measured, a step for measuring the intensity of the vibration applied to the fruit and the intensity of the vibration of the fruit, a step for measuring the weight of the fruit, a step for finding the transfer functional characteristic of the fruit by performing frequency analysis based on the intensity of the vibration applied to the fruit and the intensity of the vibration of the fruit, and computing the secondary resonance frequency f0 (i.e.

Abstract: A circuit for programmably generating a delay in a frequency monitor. In one embodiment, the circuit includes a delay cell. A delay cell controller is coupled to the delay cell. The delay cell controller is adapted to selectively control whether the delay cell is activated such that the frequency monitor can be programmably configured to have a selected delay associated therewith.

Abstract: A method and apparatus enabling information including respective angular directions to be obtained for one or more sound sources includes a sound source direction estimation section for frequency-domain and time-domain processing of sets of output signals from a microphone array to derive successive estimated angular directions of each of the sound sources. The estimated directions can be utilized by a passage detection section to detect when a sound source is currently moving past the microphone array and the direction of the sound source at the time point when such passage detection is achieved, and a motion velocity detection section which is triggered by such passage detection to calculate the velocity of the passing sound source by using successively obtained estimated directions.

Abstract: A method of measuring the period of a vehicle speed signal is disclosed that includes the steps of accumulating predetermined time interval increments between first and second rising edges of the signal, calculating a remainder time interval upon detection of the second edge of the signal and adding the remainder to the accumulated increments value to obtain the period, and calculating an average period from a plurality of consecutive period measurements. If the accumulated value exceeds a predetermined maximum value before the second edge occurs, the maximum value is used in calculating the average.

Abstract: A high-speed discrete Fourier transform (DFT) apparatus utilizes a processor operating in parallel with data acquisition to calculate terms of a Fourier transform corresponding to the incoming data. Since the processor calculates the Fourier terms in real-time, overall transformation time is substantially reduced and is limited by only the data acquisition time. In another aspect, substantial reduction of the number of computations are achieved by transforming the plurality of terms in Fourier equations at the same time. In a further aspect, the high-speed DFT is advantageously applied to a network analyzer which obtains a transfer function of a device in a frequency domain and converts the transfer function to a time domain response to a simulated test signal.

Abstract: Frequencies fx between the measurement harmonic (mth-degree harmonic) and the (m±1)th-degree harmonics are determined from an expression of fx=(fs*m)±{(fs/n)*k)} where n and k are each an integer. Currents of inter-harmonics of the frequencies fx above and below the measurement harmonic are injected into an inject point in a power system in n cycles of the fundamental wave. Voltage at the inject point based on the injected currents and currents at least either upstream or downstream from the inject point are measured. Admittances for the inter-harmonics above and below the measurement harmonic on at least either the upstream or downstream side from the harmonic inject point are calculated from the measurement results. Interpolation processing based on the calculation results is performed, thereby finding and determining an admittance for the measurement harmonic.

Abstract: A system and method for communication using movement of a person's eye, including an emitter for directing light towards an eye, a sensor for detecting emitted light from the emitter, and a processor coupled to the sensor for converting sequential light intensity signals received from the sensor into a stream of data, and/or for converting the signals into an understandable message. A radio frequency transmitter transmits the stream of data to a remote location, such as to a receiving and processing unit, which may store the stream of data, display a message in the stream of data, or use a command in the stream of data to control a piece of equipment. A self-contained detection device is also provided that includes a frame adapted to be worn on a person's head, and an emitter and a sensor, such as a solid state biosensor, on the frame for directing light towards and detecting light reflected off of the eye, respectively.

Abstract: A high sample rate cosine filter eliminates DC components by summing them such that they sum to zero. A non-orthogonal cosine filter is also provided. When the cosine filter is applied for N=4 samples per cycle, the samples are separated by 90 degrees. However, at higher sampling rates, it is not necessary to wait for 90 degrees to estimate the phasor value. Non-orthogonal components are used to estimate the phasor value. The time delay associated with the cosine filter is reduced in the process.

Abstract: A system and method for improving the ability of an electronic meter to make measurements on signals to determine content of different frequencies, and harmonics of the fundamental frequency, of AC signals (voltages and currents). The line frequency is determined and compensated for prior to performing frequency-dependent parameter measurements or determining frequency-dependent parameters.

Abstract: To determine the frequency content of a time series, a time series segment which spans a time interval is received. A time interval spanned by a symmetric tapered window with quantised elements is chosen such that the window time interval is greater than the segment time interval such that when the window is centered with respect to the segment time interval, the window element at either end of the segment time interval has the lowest available non-zero quantised value. Lastly a frequency representation of said time series may be obtained based on the time series segment and the quantised window.

Abstract: The invention relates to an improved adaptive spectral estimator for estimating the spectral components in a signal containing both an information signal, such as speech, and noise. A method and system provide for generating noise estimates and then only updating the noise estimates during pauses in an information signal, when speech or other information is not detected, rather than continuously updating the noise estimates. A noise estimate is calculated for each frequency band and provides for the inclusion of a variable mathematical factor that can be set by the user to produce the best sound quality.

Abstract: In accordance with the present invention, a method for obtaining frequency nformation about a given data set is realized. The method comprises the steps of providing a processing unit; inputting a raw data set into the processing unit; optionally removing at least one trend from the raw data; ordering the raw data; estimating power spectral density using an eigenanalysis approach and the inputted raw data and the ordered raw data; simultaneously estimating the power spectral density using the raw data and a periodogram; generating a time-series representation of the raw data to which curve fitting is applied; comparing the results from the power spectral density estimating steps and the time-series representation generating step to determine if any frequencies suggested by the eigenanalysis approach estimating step are valid; and generating an output signal representative of each valid frequency.

Abstract: A computer-implemented modeling tool for cellular telephone systems predicts signal strength under real conditions by considering the effects of terrain and man-made structures on transmitted signals. The modeling tool gives more accurate predictions under line of sight conditions, when obstructions occur due to terrain contours, and when mobile or transmitter antennas are blocked by buildings or other structures.

Abstract: In a measurement device and a measurement method for determining output values by analyzing the frequency of cyclically changing detection data, such as pulse count, the output value indicating a peak in the analysis result is corrected using side lobe values that appear on both sides of said peak, and an output value having higher precision than the output value indicating the peak value is derived, such that a value closer to the original output value of the detection data can be obtained. Because the measurement device and measurement method according to the invention can improve the precision of the output value without increasing the sampling count, highly precise output values such as pulse counts can be obtained at high speeds without extending the data fetch time.

Abstract: An antenna performance monitor comprises an antenna sensor for coupling to n antenna radiating a radio frequency signal. The antenna sensor generates signals Vm and Im representative of the antenna input voltage and current. An A/D converter is coupled to the antenna sensor for digitizing signals Vm and Im. A data processor is coupled to the A/D converter for generating outputs representative of impedance magnitude and phase angle of the antenna substantially concurrently with changes in frequency of the radio frequency signal.

Abstract: A method and apparatus for fast response and distortion measurement of a signal transfer device. A computer processor generates a multitone test signal of predetermined duration and stores it in a memory. The test signal is read out, converted to analog form, if necessary, and applied to the input of a device under test. The output produced by the device under test in response to the test signal is acquired and digitized, if necessary, and a Fast Fourier Transform is performed on the acquired data to determine its spectral characteristics. Frequency response, harmonic distortion, intermodulation distortion, phase distortion, wow and flutter and other signal transfer characteristics are measured by the CPU by analysis of the output signal.

Abstract: A frequency analyzing method according to the invention is a method of analyzing frequency components of an original signal. The method has: a spectrum detecting step of detecting, from the original signal, energy levels of components of a predetermined number of orthogonal function waves which have waveforms each having same start position and end position in a predetermined time window and in which the number of occurrences of periods in the predetermined time window or frequencies are different from each other; and an orthogonal function wave changing step of changing at least one of the start position and the end position within the predetermined time window after completion of the spectrum detecting step, wherein the spectrum detecting step and the orthogonal function wave changing step are alternately repeated.

Abstract: A stereophonic image may be enhanced by splitting the left and right input audio signals into a plurality of left and right output signals in a plurality of audio frequency bands and then generating left and right output audio signals from the left and right output signals based on the magnitude of the differences between corresponding left and right output signals and also based upon the absolute magnitude of the left and right input audio signals themselves. In particular, a stereophonic image enhancement device according to the invention processes a left input signal and a right input signal using a first spectrum analyzer and a second spectrum analyzer which output a plurality of left output signals and right output signals corresponding to a plurality of frequency bands in response to the corresponding left input signal and right input signal.

Abstract: A method and apparatus for communicating with chaotic and other waveforms employs a filter for estimating a parameter that describes a property of a signal. The filter is constructed by defining a system that models the source of the signal. The system is partitioned into a first subsystem that contains the parameter and a second subsystem that does not contain the parameter, the second subsystem including a term that makes the second subsystem stable and synchronizable with the signal. The signal is introduced as input to the second subsystem and an element of the second subsystem is substituted into a corresponding element of the first subsystem, thereby generating a signal-activated subsystem. An integration factor is introduced to the signal-activated subsystem to cause the parameter to behave as a constant when the signal-activated subsystem with the integration factor is integrated with respect to time.

Abstract: A new method of compensating for errors in phasor estimation due to oscillations caused by discrete fourier transforms used to estimate signal frequency is provided. The method uses a variable N-point DFT to compute one or more phasors based on data acquired from one or more sampled signals. At each sampling interval the change in phasor angle between the current sampling interval and the previous sampling interval is determined and used to estimate the instantaneous frequency of the signal. A non-oscillating phasor indicative of the instantaneous magnitude, angular frequency, and phase angle of the signal is generated based on the instantaneous frequency estimate. Instantaneous frequencies are averaged over a cycle of the signal to generate an average cycle frequency. In addition, a number of discrete frequencies and corresponding DFT windows based on a fixed sampling rate and a predetermined fundamental frequency of the signal are defined and used in estimating the instantaneous frequency.

Abstract: A digital programmable ultrasonic generator for driving an ultrasonic transducer includes a computer for receiving and storing a plurality of selectable programs. The programs are indicative of different modes of operation. A profile generator is coupled to the computer to receive programs and to produce a digital reference voltage indicative of a voltage profile to be generated for the mode selected. A digital frequency controller is coupled to a direct digital synthesizer for producing a predetermined frequency in response to a programmed frequency command from the computer. A process controller receives the output of the direct digital synthesizer as a voltage signal having the desired frequency and modifies the voltage depending on the mode of operation and voltage desired before driving a power amplifier coupled to the transducer to be driven.

Abstract: A method for estimating phasors and tracking the frequency of a signal during frequency ramping is provided. The method uses a variable N-point DFT periodically to compute one or more phasors based on data acquired from one or more sampled signals. The period between DFT computations is a predetermined number of sample periods. After each DFT computation, the change in phasor angle between the current phasor estimate and the most previous phasor estimate is determined and used to estimate the instantaneous frequency of the signal. The current instantaneous frequency estimate and the most previous instantaneous frequency estimate are averaged to compute an average cycle frequency. In addition, a number of discrete frequencies and corresponding DFT windows based on a fixed sampling rate and a predetermined fundamental frequency of the signal are defined and used in estimating the instantaneous frequency.

Abstract: A method and computer program product are provided for implementing a stable integral equation model for both the time and frequency domains. The stabilization method of the invention is applicable to electric field integral equation (EFIE) formulations, to magnetic field integral equation (MFIE) formulations, and to combined field integral equation (CFIE) formulations. For example, an EFIE formulation can be used in the circuit domain called partial element equivalent circuit (PEEC). Each volume cell is subdivided into a finite number of partitions. A partial inductance term is calculated consisting of a summation over all the finite number of partitions in each cell. Each surface cell is subdivided into a finite number of subcells. A coefficient of potential term is calculated consisting of a summation over all the finite number of subcells in each surface cell. Both the partial inductances and the coefficients of potential are calculated without increasing the number of unknowns.