Abstract: A technique for determining the amplitudes of frequency components of a waveform sampled from an automatic test system includes assembling a list of N frequencies expected to be found in the sampled waveform. A test program running on the tester generally supplies the list of frequencies. The technique assumes that the sampled waveform conforms to an idealized waveform model that mathematically corresponds to a sum of N sinusoids. Each of the N sinusoids that make up the model has unknown amplitude and a frequency that equals one of the N frequencies in the list of frequencies. The technique attempts to solve for the unknown amplitude of each of the N frequencies by mathematically minimizing, via a linear least-squares algorithm, the difference between the model and the actual, sampled waveform.

Abstract: There is provided a method of detecting an integrated circuit in failure among integrated circuits, based on spectrum which is a result of analyzing a frequency of a current running through an integrated circuit when a test signal is applied to the integrated circuit, comprising the steps of (a) assuming that all integrated circuits under test define a under-test integrated circuit set, and testing each one of the integrated circuits in the under-test integrated circuit set in a conventional manner, (b) removing integrated circuits having been judged to be in failure in the step (a), from the under-test integrated circuit set, (c) measuring spectrum of a current supplied from a power source into each one of the integrated circuits in the under-test integrated circuit set, (d) calculating both a mean value and standard deviation of the spectrum for the under-test integrated circuit set, (e) judging whether an integrated circuit is in failure or in no failure, based on both the mean value and the standard devia

Abstract: A frequency domain analysis system incorporated into time domain measurement instrument has duration and resolution controls that respectively adjust the acquisition time intervals of a waveform record in seconds and adjusts the number of digital data samples over a specified duration. The duration of the acquisition waveform may be controlled using the duration control adjustment, a sample rate adjustment and a record length adjustment. The resolution controls concurrently adjusts the sample rate and the record length of the acquisition waveform while maintaining the duration constant. A movable and variable length frequency spectrum gate is applied to the digital data samples of the acquired waveform. A window filter is applied to the digital data samples within the gated region a spectrum analysis generator generates frequency domain values over the gates waveform record.

Abstract: The invention illustrates a system and method of searching for a specific segment within a stream of content data comprising: receiving a stream of sensory data corresponding with the stream of content data; comparing the stream of sensory data with a search criteria; identifying the specific segment of the stream of content data corresponding to a match between the stream sensory data and the search criteria; setting the search criteria based upon parameters of the stream of sensory data; and applying a threshold to determine the match between the stream of sensory data and the search criteria.

Abstract: A spectral characterization method accurately characterizes an applied signal spectrum that has multiple, spectrally-separated signal peaks. The method detects signal peaks within the spectrum and measures the spectral content of that spectrum using a first measurement bandwidth that is sufficiently wide to encompass each of the signal peaks and accurately measure a signal component of the spectrum. Spectral content of the spectrum measured using a narrow measurement bandwidth that accurately characterizes a noise component of the spectrum. Signal-to-noise ratio for the signal peaks can be calculated based on the measurements performed using the first and second measurement bandwidths. The spectral characterization method is implemented using a spectral measurement instrument having an adjustable measurement bandwidth.

Abstract: A method and apparatus for performing an operability test on a communications system device such as a cable modem is provided. The testing method comprises the steps of providing a set of output test data to the communications system device being tested, and generating an output signal with the device in a manner that is responsive to the output test data. In the case of a cable modem, the output signal is generated by the modem's modulator. The output signal is then provided as an input to a reflective mixer which generates a reflected signal in response to the output signal and directs it back into the communications system device being tested. The communications device can then use the reflected signal to generate a set of input test data that can be compared to the output test data to check the accuracy of the device's operation.

Abstract: Specific wavelengths to use in optical metrology of an integrated circuit can be selected using one or more selection criteria and termination criteria. Wavelengths are selected using the selection criteria, and the selection of wavelengths is iterated until the termination criteria are met.

Abstract: An analog signal is digitized by an analog-to-digital (A/D) converter clocked by a periodically jittery clock signal. Elements of the digital data sequence (vector) output of the A/D converter are sorted into a set of smaller vectors according to clock signal jitter phase and each of the smaller vectors is then separately subjected to Fourier transform and time shift functions. The resulting vectors are then processed to produce an output vector representing the frequency spectrum of the analog signal.

Abstract: A signal processing method, preferably for extracting a fundamental period from a noisy, low-frequency signal, is disclosed. The signal processing method generally comprises calculating a numerical transform for a number of selected periods by multiplying signal data by discrete points of a sine and a cosine wave of varying period and summing the results. The period of the sine and cosine waves are preferably selected to have a period substantially equivalent to the period of interest when performing the transform.

Abstract: A system and method for assessing the probability of detection of a target of a hyperspectral sensing system. The system is adapted to calculate the probability of detection of targets based on various sensor parameters, atmospheric conditions, and a specified combination of targets and backgrounds for a given false alarm rate. The system may be executed, for example, on an IBM compatible PC to allow the user to optimize the hyperspectral sensor and subsequent signal processing to a particular set of backgrounds and targets. The sensor models, atmospheric models and target and background profiles are initially applied to the system in the form of the databases. As such, the system enables the user to select among the various parameters to optimize a hyperspectral sensor and the subsequent signal processing for a particular set of parameters.

Abstract: In a method of identifying a source of a signal, the signal is recorded and then analyzed in order to determine its spectrum.

Abstract: A noise reduction/resolution enhancement signal processing method and system is disclosed, wherein the influence of noise spikes and gaps is substantially reduced. The data for the noise reduction may be amplitudes (bx) measured at corresponding values (x) over a given domain D, wherein the data defines a composite wave form. The composite wave form is decomposed into instances of a discrete wave form, each having reduced noise amplitudes. A candidate point c in D for, e.g., an amplitude extreme is determined for each discrete wave form instance (having unknown amplitude). A minimization technique determines a first set of discrete wave form instances (having known amplitudes) by collapsing on the amplitudes (bx) from above. A maximization technique determines a second set of discrete wave form instances (having known amplitudes) by rising up to the amplitudes (bx) from below.

Abstract: A magnetic flow transmitter provides a coil driver output at a selected fundamental to a coil on a flow tube carrying a flow of a liquid. An amplifier amplifies an electrode signal from the flow tube and an A/D converter converts the amplified electrode signal. A digital signal processor (DSP) uses a spectral transform such as a Fourier type transform to generate a flow output based on spectral components at or near the fundamental and a noise diagnosing output based on components at or near a noise frequency.

Abstract: A method for identifying spectral impulses applies a window filter to an acquired waveform to produce a filtered waveform, and performs an FFT function on the filtered waveform to produce a spectrum of bins. An estimating window is located on the spectrum and centered on a target bin. Bins adjacent to the target bin are excluded and the remaining bins are used to form a noise estimate. The estimate is compared to the target bin and if the result exceeds a threshold value, a spectral impulse is identified.

Abstract: Disclosed is a method and system for measurement of periodic gratings which have deviations which result in more than two materials occurring along at least one line in the periodic direction. A periodic grating is divided into a plurality of hypothetical layers, each hypothetical layer having a normal vector orthogonal to the direction of periodicity, each hypothetical layer having a single material within any line parallel to the normal vector, and at least one of the hypothetical layers having at least three materials along a line in the direction of periodicity. A harmonic expansion of the permittivity &egr; or inverse permittivity 1/&egr; is performed along the direction of periodicity for each of the layers including the layer which includes the first, second and third materials.

Abstract: A method for measuring a bandwidth of a signal path between a data source and a data recipient involves sending a block of test data from the data source along the signal path to the data recipient, using that test data to obtain a measured bandwidth of the signal path, and transferring information from the data source along the signal path to the data recipient in accordance with the measured bandwidth. The measured bandwidth value can be calculated each time the data recipient accesses a website or the measured bandwidth value can be retained for future use.

Abstract: A pulse management system configured to perform a plurality of pulse measurements on each of a plurality of pulses of an acquired signal and to store results of the pulse measurements in an accessible data structure. The pulse management system includes a pulse analyzer that searches the data structure for pulses of the acquired signal that satisfy operator-provided search criteria. Similarly, the pulse analyzer can sort the selected subset of pulses based on sort criteria provided, for example, by an operator. The pulse analyzer can provide the operator with a user interface environment in which the operator specifies the search and sort criteria and in which the pulse analyzer displays the selected pulses with their associated pulse measurement results. The operator can advance through the selected pulses in any manner desired to display different pulses together or separately.

Abstract: A field distribution measuring method for measuring a spatial distribution of an electric field or a magnetic fields at a plurality of sampling points by the probe continuously sweeping the sampling points, in which, based on spurious spectra generated by offsets between positions of the probe and measuring timings, a shift amount of the sampling points is computed, and, taking into account the shift amount, a distribution of electric fields or magnetic fields is measured. Thus, measured noises generated due to offsets between sweeping positions of the probe and measuring timings can be properly removed.

Abstract: A linear multichannel detection system for billing by spectrum convolution applicable in telecommunications systems, capable of detecting the metering pulses in a signal sent from a telephone exchange to the subscribers, multiplying the signal by a specific signal generated by the system and measuring powers corresponding to the signals resulting from the multiplication, in such a way that a power measured with a value greater than a predefined threshold value indicates detection of the pulse. The invention likewise refers to an access system including the detection system.

Abstract: An ultrasound transmitter generates ultrasound signals at an adjustable pulse repetition rate. A Doppler unit generates Doppler signals from ultrasound backscattered signals and stores them in a memory. A logic unit performs an algorithm which automatically adjusts the polarity and position of the velocity scale of a display and automatically adjusts the pule repetition rate of the transmitter based on analysis of the signals.

Abstract: A signal processing technique can be effectively used for source separation, signal enhancement, and noise reduction when using a twin microphone system. The class of stochastic signals for which ratio-estimates can be computed from histograms is defined. This class fits real-world signals of interest such as voice signals. Theoretical computation in closed form of the optimal estimator for this class of signals is disclosed. Two practical implementation solutions are disclosed, as is a practical solution to exploit an echoic environment model. Furthermore, two novel techniques for signal demixing are presented. The application of the optimal estimator and the suboptimal estimator to the case of more than two channels is disclosed.

Abstract: A spectrum analysis method and apparatus for processing and displaying time series data. The time series data in digital form is decomposed into a plurality of frequency components by means of a set of band pass filters. Adjacent band pass filters have their cut-off frequencies shifted or offset from each other by their passing band widths. Amplitude information of the frequency components may be obtained. For example, the frequency components generated by the band pass filters may be sampled in amplitude at predetermined time intervals. Such sampled amplitudes are then transformed into corresponding densities of a predetermined color including a gray color according to a color (or gray) scale, and displayed on a screen on the basis of a time base of the screen.

Abstract: Spectrum estimates of unevenly spaced timestamped data collected over a network. Unevenly spaced data is not suitable for processing by traditional methods such as Fast Fourier Transforms. Spectrum estimates of timestamped data collected over a network are calculated using a Continuous Fourier Transform. If the time between samples is long, spectrum estimates may be computed incrementally.

Abstract: Repetitive sampling of a data signal is performed. A clock reference is generated. The clock reference has a known period relationship with the data signal. The clock reference and the data signal are simultaneously sampled. The sampled information from the clock reference is used to determine in what phase of the clock reference sampled values of the data signal occur.

Abstract: A novel test structure is described which can be used to accurately measure on-wafer impedances. For example, accurate measurements of the parasitic capacitances inside active devices such as Field Effect Transistors or the capacitance of interconnect lines with either the substrate or with each other can be made. The test technique involves frequency sweep S-parameter power measurements made in the range of 50 MHz to about 20 GHz. One or more identical copies of the DUT are connected on the wafer with one or more on-wafer inductances which are usually lumped, to form a two port circuit. The circuit is essentially a filter operating in the frequency range of 50 MHz to 20 GHz. Although filter circuits are normally designed to provide a flat response in the pass and stop bands, with as sharp a skirt as possible, the objective in designing this test circuit is to design a filter response with sharp inflection points that are uniquely dependent on the reactances that comprise the filter circuit.

Abstract: By using a reconstruction algorithm, based on the spectral characteristics of the illumination source and a color sensing system, a spectral curve reconstruction device converts measurements from a non-fully illuminant populated color sensor into a fully populated spectral curve. This is done using a spectral measurement system model, which may use basis vectors.

Abstract: A method and system for monitoring at least one of a system, a process and a data source. A method and system have been developed for carrying out surveillance, testing and modification of an ongoing process or other source of data, such as a spectroscopic examination. A signal from the system under surveillance is collected and compared with a reference signal, a frequency domain transformation carried out for the system signal and reference signal, a frequency domain difference function established. The process is then repeated until a full range of data is accumulated over the time domain and a Sequential Probability Ratio Test methodology applied to determine a three-dimensional surface plot characteristic of the operating state of the system under surveillance.

Abstract: A method and apparatus for selecting an optimum frequency for driving a transducer in a megasonic cleaning system. The method comprises the steps of selecting a plurality of frequency values that span a frequency range containing an optimum frequency for driving a piezoelectric crystal, determining the reflection coefficient at each frequency value, fitting the data set to a function, obtaining the first derivative equation of the function, finding the roots of the first derivative equation to yield a set of roots, and selecting the optimum frequency from the set of roots. The reflection coefficient is defined as the reflected power divided by the forward power. The apparatus comprises a microprocessor, a frequency generator, a directional coupler/detector and an analog to digital converter circuit.

Abstract: An automated method for modeling spectral data is provided, wherein the spectral data generated by one of diffuse reflectance, clear transmission, or diffuse transmission. The method includes accessing a set of spectral data, the set of spectral data including, corresponding spectral data for each of a plurality of samples, the spectral data for each of the plurality of samples having associated therewith at least one constituent value, the at least one constituent value being a reference value for a target substance in the sample which is measured by a independent measurement technique. A plurality of data transforms are applied to the set of spectral data to generate, for each sample, a set of transformed and untransformed spectral data.

Abstract: An ultrasonic RFI source locator implements signal analysis to discriminate ultrasonic shocks emanating from power line equipment sources from ambient and other interference sources, as well as distinguish between specific type interference sources, such as corona and sparking discharge. The locator has a directional or contact ultrasonic sensor for receiving a signal representing the ultrasonic shocks from a targeted source, and includes signal processing circuitry to detect and compare the strengths of portions of the sensed signal that are modulated at whole integer multiples (harmonics) of an electrical power frequency (e.g., at 60 Hz and 120 Hz on a 60 Hz A/C power system, or 50 Hz and 100 Hz on a 50 Hz A/C power system) with each other, with the total signal and with selected non harmonic frequencies. The locator provides an operator indication of the result of this spectral analysis.

Abstract: Provided is a method of measuring impedance based on carrier function Laplace transform, comprising the steps of:

Abstract: A wavelet generator for defining wavelets that represent a first signal includes a programmable filter bank, a frequency band controller coupled to the programmable filter bank, and a wavelet constructor coupled to the programmable filter bank. The programmable filter bank is operable to receive the first signal, and filter the first signal based upon a plurality of frequency bands to obtain a plurality of frequency band signals that each represent a frequency band of the first signal. The frequency band controller is also operable to receive the first signal. Moreover, the frequency band controller is further operable to obtain the plurality of frequency bands from the first signal, and program the programmable filter bank with the plurality of frequency bands. The wavelet constructor is operable to receive the plurality of frequency band signals.

Abstract: A vector network analyzer (VNA) is provided with three test ports and an integration of hardware and software to make an integrated set of measurements for two and three port devices. The integrated capability allows for fast, versatile measurements that benefits, in accuracy and convenience, from sharing of data and resources with other measurements. The VNA includes a first signal source which is selectively connectable through reflectometers to two of the three VNA test ports. A second signal source provides connection through a third reflectometer to a third test port to enable full vector error corrected 3-port S-parameters measurements to be made. The two signal sources, along with software configuration of the VNA to operate in a non-ratioed mode provides for measuring second and third order intercept measurements. The two signal sources and software also enable the VNA to be used to make frequency translation measurements of a mixer including accurate frequency translation group delay measurements.

Abstract: A jig is successively mounted on each of the four wheels of a vehicle. The jig is struck in three orthogonal directions independently, and at the same time, a microphone inside the vehicle measures the sound pressure of noise generated due to the exciting force. An FFT analyzer operates a frequency response function from the exciting force to the sound pressure. In a drum testing machine, a tire to be subject to noise prediction is mounted on a shaft, the tire is rotated, and the axial force in the three orthogonal directions is measured. The axial force signal is input to the FFT analyzer and the auto power spectrum in the three orthogonal directions and the cross power spectrum between two different axial directions are operated. The frequency response functions are synthesized with the auto power and cross power spectrums, and the power spectrum of the road noise is operated.

Abstract: A system and method for estimating parameters of multiple tones in an input signal. The method includes receiving samples of the input signal, generating a frequency transform (FT) of the samples, identifying multiple amplitude peaks in the FT corresponding to the tones, and determining parameter estimates characterizing each of the multiple tones based on the peaks. For each tone, the effects of the other tones are removed from the FT of the peak of the tone using the parameter estimates of the other tones to generate modified FT data for the tone. Single tone estimation is applied to the modified FT data to generating refined parameter estimates of the tone, which is used to update the parameter estimates of the tone. After refining the estimates for each tone, the entire process may be repeated one or more times using successive refined estimates to generate final estimates for the parameters.

Abstract: A system and method for estimating signal parameters (e.g., one or more of frequency, amplitude and/or phase) of one or more tones present in an input signal. The method may comprise first receiving samples of the input signal, wherein the input signal includes the tone, and generating a frequency transform of the samples. The method may then identify an amplitude peak in the frequency transform corresponding to the tone. Two or more frequency bins may then be selected proximate to the identified frequency location in the frequency transform. The method may then determine a tone frequency value that minimizes a difference between two or more expressions. The expressions include numerator and denominator terms that correspond to respective frequency bins, wherein a ratio of each numerator term and its corresponding denominator term represent a complex amplitude of the tone at a respective bin.

Abstract: A method of determining distance to fault of a transient event in a transmission system uses per frequency triggered I and Q data representing voltage and phase of a return signal in the frequency domain. Initially a result set of data entries, one for each discrete frequency in a specified frequency range, is filled with zeros and an initial acquisition set of per frequency I and Q data from the transmission system is used to fill a reference set of data entries. Subsequent acquisitions of per frequency data sets are used to fill a current set of data entries. Between each acquisition of data sets for the current set a comparison is made, entry by entry, between the current set and the reference set, and the data from the current set is used to update the corresponding entry in the result set when the difference exceeds a specified tolerance.

Abstract: Improved approaches to assist those having hearing loss are disclosed. One approach pertains to providing on-line hearing loss testing. The on-line hearing loss testing can be self-performed without any specialized equipment. Another approach pertains to on-line sound customization. The sound customization can simulate hearing compensation on-line. As an example, the hearing compensation can be used to simulate hearing aid processing. Still another approach pertains to a recommendation and/or referral procedure.

Abstract: A method for characterizing a dual frequency (DF) signal including the steps of sampling the signal at a sampling frequency vs so as to obtain a sequence of signal samples, and obtaining an &agr;-constant and a &bgr;-constant of the DF signal meeting a predetermined criterion.

Abstract: A technique for determining the amplitudes of frequency components of a waveform sampled from an automatic test system includes assembling a list of N frequencies expected to be found in the sampled waveform. A test program running on the tester generally supplies the list of frequencies. The technique assumes that the sampled waveform conforms to an idealized waveform model that mathematically corresponds to a sum of N sinusoids. Each of the N sinusoids that make up the model has unknown amplitude and a frequency that equals one of the N frequencies in the list of frequencies. The technique attempts to solve for the unknown amplitude of each of the N frequencies by mathematically minimizing, via a linear least-squares algorithm, the difference between the model and the actual, sampled waveform.

Abstract: Process and device for reducing the spectral line noise inside an aircraft, especially a rotating-wing aircraft, in particular a helicopter. Said device (1) comprises sensors (Ca, Cb) for measuring the values of vibratory and/or acoustic parameters, controllable mechanical elements (A) forming secondary sources of noise, and a main computer (CAL) determining, on the basis of the values measured by the sensors (Ca, Cb), control commands for the mechanical elements (A), as well as at least one reference sensor (CO) for measuring a reference parameter which is correlated with the noise, and possibly an auxiliary computer (4) for calculating, on the basis of the values measured by the reference sensor (CO), a reference signal, and said main computer (CAL) determines the control commands by carrying out filtering with respect to the reference signal.

Abstract: A method of measuring impedance is based on carrier function Laplace transform. The measurement includes detecting a response signal from a device under test, to which signal an excitation such as a pulse, interrupt or constant load is applied. Resulting data is fitted to a carrier function, selected so as to be capable of providing a good fit and for which an analytical Laplace transform is known, in order to obtain parameters of such function providing best fit. Obtained parameters are further substituted into the analytical expression of Laplace transform of carrier function which is used to calculate a frequency dependent impedance function in the Laplace domain. The resulting impedance function is used for calculating the impedance spectrum in a frequency domain and for calculating the measurement error of the frequency domain impedance spectrum using the standard deviations of the parameters, obtained during fitting of time-domain data.

Abstract: A method and system for generating a noise index for a mechanical system in which noise data is acquired over a predetermined frequency range. A fundamental harmonic frequency is chosen and this fundamental harmonic frequency is used to mark harmonic and sub-harmonic data bins. The amplitude of the harmonic and sub-harmonic data bins are recorded and a plurality of sub-harmonic bins equally offset from the center of each harmonic frequency are averaged and the average is subtracted from the preceding harmonic level. The result is accumulated as harmonic content levels to generate a harmonic index number.

Abstract: FFT section 102 transforms a windowed input noise signal into a frequency spectrum. Spectral model storing section 103 stores model information on spectral models. Spectral model series calculating section 104 calculates spectral model number series corresponding to amplitude spectral series of the input noise signal, using the model information stored in spectral model storing section 103. Duration model/transition probability calculating section 105 outputs model parameters using the spectral model number series calculated in spectral model series calculating section 104. It is thereby possible to synthesize a background noise with perceptual high quality.

Abstract: A method and apparatus for rejecting signals exhibiting pulse pile-up and devices incorporating the method and/or apparatus. A pulse sensor senses pulses and an analog-to-digital converter digitizes the sensed pulses into discrete ADC values over a plurality of time slices. The digitized pulses are stored in a FIFO memory for processing by a classification processor. The processor qualifies the pulse and marks its first time slice. The processor includes accumulators that calculate parameters from various regions of the pulse. The calculated parameters are compared to criteria from identical regions of known, non-piled pulses. Pulses whose calculated parameters meet the criteria are accepted and stored in one memory location, and pulses whose calculated parameter do not meet the criteria are rejected and stored in another memory location.

Abstract: An ultrasound transmitter generates ultrasound signals at an adjustable pulse repetition rate. A Doppler unit generates Doppler signals from ultrasound backscattered signals and stores them in a memory. A logic unit performs an algorithm which automatically adjusts the polarity and position of the velocity scale of a display and automatically adjusts the pule repetition rate of the transmitter based on analysis of the signals.

Abstract: The spectral energy in the signal emitted by a mobile telephone handset is measured for portions of the signal carrying random data, both before and after a non-random midamble. By including both random portions in the measurement the time taken to perform it is approximately halved, whilst maintaining its statistical significance.

Abstract: A data processing system and method included within an oscilloscope for independently analyzing a signal input into the oscilloscope. The oscilloscope includes a plurality of triggering modes. A plurality of trigger parameters are specified for each of the triggering modes. Thereafter, the oscilloscope automatically analyzes the input signal, independently from any user input, utilizing each of the triggering modes and the trigger parameters specified for each of the triggering modes. The input signal includes a desired waveform and a plurality of undesired waveforms. While the oscilloscope is automatically analyzing the input signal, a determination is made regarding whether the oscilloscope triggered on one of the undesired waveforms. When it is determined that the oscilloscope triggered on one of the undesired waveforms, the undesired waveform upon which the oscilloscope triggered is stored.

Abstract: An iterative method and apparatus for correction and compensation of analytical signals, such as spectrometric data, is provided which corrects for spectral cross-talk; compensates for spectral shift; and reduces error propagation. The method and apparatus can be applied to a multicomponent sample analysis using least squares procedure with differentiation while reducing noise propagation.

Abstract: A method for determining the value of at least one capacitance required to be placed in a conductive path on a printed circuit board is disclosed. The method includes preparing a desired signal spectrum for the conductive path, preparing an actual signal spectrum for the conductive path, and then comparing the actual signal spectrum against the desired signal spectrum to determine where any out of tolerance conditions exist. If the actual signal spectrum is in amplitude versus time form, the method further includes performing, for each time having a voltage which is higher than the maximum voltage allowed on the conductive path, a fourier transform on the amplitude versus time data.