Abstract: Spectra obtained from spectrographic readings from a sample can be filtered for artifacts, e.g., distorted data points arising from cosmic ray interference, by subtracting one spectrum from another to obtain a difference spectrum; smoothing the difference spectrum; and then calculating the difference between the smoothed and unsmoothed difference spectra to obtain a noise spectrum. The resulting noise spectrum, which represents localized differences between the original spectra, can then be reviewed for readings which exceed the norm by some predetermined amount (e.g., readings which exceed the average level of the noise spectrum by some percentage). These excessive readings constitute distorted data points, and the corresponding points on the spectra can have their values adjusted to eliminate the excessive readings, thereby removing the artifacts.

Abstract: Novel excitation signals are specifically designed for testing a high-frequency mixer such that all of the desired intermodulation products are measurable after being converted by a sampling frequency converter. This is achieved by using excitation frequencies which are equal to an integer multiple of the sampling frequency of the sampling frequency convertor plus or minus small frequency offsets. The offset frequencies are carefully choosen such that the frequencies of all the significant intermodulation products after being converted by the sampling frequency converter are within the bandwidth of the sampling frequency converter output.

Abstract: A method and apparatus for digitizing a signal. The method comprises the steps of receiving an input analog signal, splitting the received input analog signal into a plurality of signals and frequency converting at least one of the signals in accordance with a predetermined periodic function having a predetermined frequency. The signals are then digitized and combined mathematically to form a single output stream that is a substantially correct representation of the original input analog signal.

Abstract: A method for improving bandwidth of an oscilloscope involves, in preferred embodiments, the use of frequency up-conversion and down-conversion techniques. In an illustrative embodiment the technique involves separating an input signal into a high frequency content and a low frequency content, down-converting the high frequency content in the analog domain so that it may be processed by the oscilloscope's analog front end, digitizing the low frequency content and the down-converted high frequency content, and forming a digital representation of the received analog signal from the digitized low frequency content and high frequency content.

Abstract: Method and system are disclosed for determining individual string resistance in a network of strings when the current through a parallel connected string is unknown and when the voltage across a series connected string is unknown. The method/system of the invention involves connecting one or more frequency-varying impedance components with known electrical characteristics to each string and applying a frequency-varying input signal to the network of strings. The frequency-varying impedance components may be one or more capacitors, inductors, or both, and are selected so that each string is uniquely identifiable in the output signal resulting from the frequency-varying input signal. Numerical methods, such as non-linear regression, may then be used to resolve the resistance associated with each string.

Abstract: A method and system for solving the inverse acoustic scattering problem using an iterative approach with consideration of half-off-shell transition matrix elements (near-field) information, where the Volterra inverse series correctly predicts the first two moments of the interaction, while the Fredholm inverse series is correct only for the first moment and that the Volterra approach provides a method for exactly obtaining interactions which can be written as a sum of delta functions.

Abstract: Systems and methods are disclosed for identifying recurrent patterns. In one embodiment, a method comprises: estimating a power spectral density of a time series; determining a duration-level associated with a peak in the power spectral density; and aggregating the time series at the duration-level to obtain a recurrent pattern.

Abstract: A computer-implemented process and apparatus for automatically identifying compounds in a sample mixture. The process involves receiving a a representation of a measured condition of the sample mixture, using the representation of a measured condition of the sample mixture to select a set of reference spectra of compounds suspected to be contained in the sample mixture, from a library of reference spectra, receiving a representation of a test spectrum having peaks associated with compounds therein, the test spectrum being produced from the sample mixture under the measured condition and combining reference spectra from the set of reference spectra to produce a matching composite spectrum having peaks associated with at least some of the suspected compounds, that match peaks in the test spectrum, the compounds associated with the reference spectra that combine to produce the matching spectrum being indicative of the compounds in the sample mixture.

Abstract: An algorithm is provided for a frequency domain reflectometer which takes into account both attenuation per unit length of transmission line and phase shift per unit length of transmission line in a modified Inverse Fourier Transform that converts a frequency domain complex reflection coefficient into a more accurate time domain reflection coefficient so that the distance to a fault can be readily determined.

Abstract: The apparatus reduces the amount of correction for noise value error, so as to reduce work needed for correction to ensure error avoidance, and to improve the freedom of layout design, and to reduce load on DA. Based on a timing chart of signal transfer on each wire, the last edge appearance timing in the signal waveform of a victim whose noise value exceeds a limit value is compared with the last edge appearance timing in the signal waveform of an aggressor, to evaluate the noise value error in the victim. The apparatus is used in static noise checking of cell arrangement and inter-cell wiring after such cell arrangement and inter-cell wiring are performed at design of integrated circuits such as LSIs.

Abstract: A method of controlling the quality and/or condition of a fibre web in a process for manufacturing and/or finishing the fibre web, which includes, monitoring the fibre web with at least one optical spectrum separating measurement device, determining a quality variable of the fibre web, measuring electromagnetic radiation reflected from the fibre web using an optical spectrum separating measurement device synchronously with a movement of the fibre web, and measurements in the form of spectral data, generating a continuous quality variable chart, dividing the continuous quality variable chart into successive matched partial charts having a cycle length, detecting deviations and/or discontinuities of the quality variable from the successive matched partial charts, and detecting malfunctioning of a rotating/moving means using the detected deviations and/or discontinuities of the quality variable.

Abstract: A self-calibrating sigma-delta converter (SCADC) functions in a calibration mode and in an operational mode. In the calibration mode, a test circuit of the SCADC generates test signals that are periodic rectangular voltage waveforms. Each test signal has a dc component with a precise voltage amplitude, as well as harmonic components. A low-pass filter of a sigma-delta converter (SDC) within the SCADC filters out the harmonic components. A digital calibration processing circuit within the SCADC uses the precise voltage amplitudes to generate digital correction factors that compensate for dc offset error, gain error and INL error of the SDC. In the operational mode, the SDC receives an analog operational signal and outputs an operational digital data stream. The digital calibration processing circuit uses the correction factors to compensate for dc offset error, gain error and INL error in the operational digital data stream and outputs a corrected digital data stream.

Abstract: A method and apparatus for digitizing a data signal, the method comprising the steps of receiving an input analog data signal, splitting the received input analog data signal into a plurality of split signals, and mixing at least one of the split signals with a predetermined periodic function with a predetermined frequency. The split signals are then digitized and combined mathematically to form a single output data stream that is a substantially correct representation of the original input signal.

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 spectrum analyzer with a compensation circuitry for prevention of measurement accuracy deterioration due to local oscillators phase noise.

Abstract: A scheme to provide a spectral view of the signals present at the customer premises equipment by the network operator and includes a digital signal processor (DSP) or other signal processing apparatus integrated into a customer premises equipment (CPE) tuner in which the DSP or other signal processing apparatus is operational to perform a spectral analysis.

Abstract: A method of using a vector network analyzer (VNA) for coordinated Voltage Standing-Wave Ratio (VSWR) and Time Domain Reflectometry (TDR) measurement includes configuring the VNA for identifying discontinuities correlated to a VSWR lobe. In some embodiments, the method includes identifying a largest VSWR lobe in a frequency band of interest, using phase data associated with an S11 scattering parameter to find the correct electrical delay required to align Low Pass Step Transform data, and configuring the Low Pass Step Transform span and center time to align coherent inductive and capacitive discontinuities relative to grid lines of a TDR display. In some embodiments, the method is automated.

Abstract: A method of determining at least one parameter of a waveguide (3) from wavefield data acquired from wave propagation in the waveguide including obtaining first and second dispersion curves (9a, 9b, 9c) in the frequency domain from the wavefield data. A frequency interval between the first dispersion curve and the second dispersion curve is found, and this is used in the determination of at least one parameter of the waveguide. The frequency separation ?ƒ(V) between the first and second dispersion curves may be found at a particular value of the phase velocity V, and the thickness h of the waveguide can be found using: ? ? ? f ? ( V ) = c 1 2 ? h ? 1 - c 1 2 V 2 Here, c1 is the velocity of wave propagation in the waveguide. This may be found from the asymptotic velocity values of the dispersion curves.

Abstract: A method for determining the frequency of current ripples contained in the armature current signal of a commutated direct current (DC) motor includes determining frequency spectral results of the current signal and of a motor electric operating parameter. The frequency spectral results are subtracted from one another to determine the frequency spectral result of the current ripples contained in the current signal. The current ripple frequency is determined from the frequency spectral result of the current ripples contained in the current signal. The operating parameter may be the armature voltage signal, or the armature current signal at a different motor operating state than the motor operating state of the current signal used in the step of determining the current signal frequency spectral result. The rotational speed of a motor shaft is determined based on the current ripple frequency. The shaft rotational position is determined based on the rotational shaft speed.

Abstract: The invention refers to a method of resonance spectroscopy for the analysis of statistical properties of samples, comprising the following steps: a) recording of a complex resonance frequency spectrum of each sample by means of phase sensitive quadrature detection; b) numerical differentiation of the recorded complex resonance frequency spectra versus frequency; c) determination of the absolute value of each differentiated complex resonance frequency spectrum (=fingerprint); d) allocation of each fingerprint to a point of a multidimensional point set; and e) performing a pattern analysis of the generated points for characterizing the statistical properties of the samples. The inventive method tolerates unintended variances of measurement in the recorded resonance frequency spectra, in particular caused by phase errors, and allows reliable automated spectral analysis.

Abstract: To measure the effective directivity and/or the effective source port match of a test port of a system-calibrated vector network analyser, a precision air line short-circuited at the outlet is connected, and the complex reflection coefficient is measured at the inlet of this precision air line at a sequence of measuring points within a predefined frequency range. At the same time, for the effective directivity the sequence of the measured complex reflection coefficients is subjected to a discrete Fourier transformation and the baseband filtered out of the spectrum thereby formed. The sequence of effective directivity values is obtained by subsequent inverse Fourier retransformation.

Abstract: In testing a distributed feedback semiconductor laser with a grating having a phase shift part, a spectrum of the distributed feedback semiconductor laser is measured. A difference between an intensity of a side mode at a high-frequency-wave side of a main mode and an intensity of a side mode at a low-frequency-wave side of the main mode is calculated. The distributed feedback semiconductor laser is judged non-defective when the difference is more than a certain value.

Abstract: A system to acoustically monitor at least one wind power installation, wherein the wind power installation includes a plurality of components including at least rotor blades. The system may comprise a remote monitoring center and a first wind power installation. The first wind power installation includes a sound pick-up device to detect an operating acoustic spectrum generated by at least one of the components of the first wind power installation during operation thereof, and circuitry to detect when a deviation between the operating acoustic spectrum of the first wind power installation and a reference spectrum exceeds a threshold. The system, in one aspect, may further include communications circuitry to communicate a fault message to the remote monitoring center when the deviation exceeds a threshold. The system may also include a remote monitoring center to monitor the operation of the first wind power installation.

Abstract: Frequency rectification system using a Van der Pol oscillator for processing an asset signal by obtaining a complex signal from an asset comprised of a noise signal and a signal of interest having a corresponding frequency of interest wherein the complex signal includes a first spectrum having all of its largest spectral peaks corresponding to the noise signal such that the signal of interest is hidden under the noise signal. The system processes the complex signal with the Van der Pol oscillator with selected parameters for rectifying the complex signal into a rectified signal such that the noise signal is abated and the rectified signal is comprised of a second spectrum having a largest spectral peak corresponding to the signal of interest with all other spectral peaks smaller. The system extracts the frequency of interest from the rectified signal with an extraction module for use in providing asset information.

Abstract: A manufacturing apparatus which includes a rotary machine, includes: a plurality of accelerometers configured to measure diagnosis time series data attached to the rotary machine at locations where variations of the rotary machine are different; a frequency analysis device configured to perform a frequency analysis on the diagnosis time series data measured by the plurality of accelerometers; a time series data recording module configured to generate diagnosis data based on variations in characteristics of vibration corresponding to an analysis target frequency and to record the diagnosis data; and a life prediction unit configured to analyze the diagnosis data to determine a life span of the rotary machine.

Abstract: A frequency harmonic identifier for detecting series arcs on a power line includes a frequency analyzer for providing the harmonic content of a sensed current signal and a decision logic for comparing a tested signal to at least one reference signal band. The reference signal band or bands may represent a variety of common loads and if the tested signal does not match any of the sets of reference signal bands, then the logic determines the tested signal to be a series arc signal. The frequency harmonic identifier may be provided within a circuit interrupter and may issue a trip signal if the tested signal is determined to be a series arc signal. Also disclosed is a method for detecting series arcs, and a storage medium having instructions for causing a computer to implement the method.

Abstract: A frequency converter is tested. Labels for a plurality of mixing products are displayed. In response to a user selecting a first mixing product from the plurality of mixing products, appropriate frequencies for the first mixing product are calculated. Also, a measurement configuration for the first mixing product is determined.

Abstract: A method and apparatus for digitizing a data signal. An input analog data signal, is received and split into a plurality of split signals. At least one of the split signals is mixed with a predetermined periodic function with a predetermined frequency. The split signals are then digitized and combined mathematically to form a single output data stream that is a substantially correct representation of the original input signal.

Abstract: An improved method and system for detecting covert surveillance devices uses frequency spectrum traces produced by a spectrum analyzer. The electromagnetic spectrum is scanned in a reference area to produce a reference frequency spectrum trace. The electromagnetic spectrum is then continuously scanned in a nearby target area to produce a peak hold frequency spectrum trace. The reference frequency spectrum trace is then subtracted from the peak hold spectrum trace to produce a comparative frequency spectrum trace. Peaks in the comparative frequency spectrum correspond to signals that are unique to either the reference area or the target area or transitory in nature. Statistical analysis is performed on subsequently obtained frequency traces to identify any changes in the frequency traces.

Abstract: A dynamic model of non-linear tuning behavior is used to tune a tunable device. The model quantifies a difference between a tuning characteristic of an ideal device and an actual tuning characteristic of the device. The model adjusts the tuning according to the difference. A method of compensated tuning of tunable device comprises employing a dynamic model of the tunable device to produce a compensated tuning control input to the tunable device during tuning. A tuning compensator for a tunable device comprises the dynamic model that is employed with an input tuning command to generate a compensated tuning command. A tuning-compensated YTF comprises a dynamic model-based tuning compensator and a YTF. A spectrum analyzer having a tuning-compensated preselector comprises a YTF preselector, a frequency converter, a video signal processor unit, a tuning compensator, and a controller. The tuning compensator uses the dynamic model to tune the preselector.

Abstract: A method and system characterize jitter of an applied signal. The characterization includes acquiring a set of pseudo-randomly timed samples at a designated position on the signal, assigning a jitter value to each of the pseudo-randomly timed samples in the acquired set, and selecting a frequency from an array of frequencies based on a correlation of the assigned jitter values with the frequencies in the array. The periodic jitter associated with the signal is designated to have the frequency within the array of frequencies that has the highest correlation to the assigned jitter values.

Abstract: A multirate spectral analyzer receives a data sequence through a tapped delay line (510) onto a plurality of filter channels, each of which includes a first decimator (520), a polyphase filter (530), and a second decimator (540). Each filter channel is coupled to a transform processor (550) which modulates the frequency response of the polyphase filters to a plurality of identical bandpass filters spaced evenly at 2?k/M intervals, where k=1, 2, . . . , M?1, and M is the number of filter channels. The transform processor (550) outputs a plurality of time series representative of the frequency component for each of the corresponding filter channels. By choosing a prototype filter order to be much larger than the number of filter channels, the effects of aliasing in the output are greatly reduced. The reduction in aliasing further allows, by prudent selection of the two decimators, for fractional temporal overlap to be implemented in the spectral estimates.

Abstract: Methods, systems, and articles of manufacture consistent with the present invention provide for determining the location of a short circuit in a branched wiring system. The distance from the short circuit to an impedance measurement point is determined based on a measured impedance of the branched wiring system. The branch in which the short circuit is located is then determined by identifying a calculated high-frequency impedance phase spectrum for the branched wiring system with one of the branches short-circuited that correlates to a measured high-frequency impedance phase spectrum for the branched wiring system. The measured high-frequency impedance phase spectrum is measured from the impedance measurement point.

Abstract: A diagnostic apparatus and method for sensing a signal emanating from a machine and determining a periodic machine event based on the emanated signal. The apparatus includes analog to digital processing components for digitizing the sensed signal, producing a digitized signal. The apparatus also includes a transform algorithm, memory, an analysis algorithm, and a display. The transform algorithm transforms the digitized signal to generate power spectral density and autocorrelation data which is stored in the memory. The analysis algorithm includes criteria for analyzing the stored power spectral density and autocorrelation data to determine a period machine event based at least in part upon the autocorrelation data. The display displays the periodic machine event to a user. In the event of a suspected defect or fault, the device alerts the user. The user may then elect to proceed with repairs or undertake advanced analysis of the suspected fault as economy dictates.

Abstract: A channel plan with a corresponding test plan are implemented in connection with a plurality of nodes that communicate signals. The channel plan has one or more predefined specifications for each of one or more signal channels on each of the nodes. The channel plan enables a monitoring system to, among other things, conduct automatic periodic test plans, comprising tests, on the nodes, based upon the predefined data specified in the channel plan. Each test plan prescribes measurement of at least one signal parameter, pertaining to one or more nodes as a whole and/or to one or more channels contained within the nodes. The monitoring system includes a spectrum analyzer, a switch enabling the spectrum analyzer to interface with the nodes, and a controller controlling the switch and the spectrum analyzer. The controller is configured to enable creation of and display the channel plan and test plan, based upon user inputs.

Abstract: A system for identifying a signal source in a predetermined space, the system including multiple sensing units arranged at different locations to detect signals in the predetermined space. The system also includes one or more recording units arranged to separately and simultaneously record a detected signal at each of the sensing units that detects the signal. The system further includes a processing unit including a first storage area configured to store a set of identified signatures corresponding to multiple signal sources in the predetermined space, and a second storage area configured to store parameters related to the conditions under which the recordings of the signal are made. The processing unit also includes an identifying unit that is programmed to identify a signal source by comparing a determined signal spectrum with some or all of the signatures included in the set of identified signatures.

Abstract: This invention presents a method for computing Instantaneous Frequency by applying Empirical Mode Decomposition to a signal and using Generalized Zero-Crossing (GZC) and Extrema Sifting. The GZC approach is the most direct, local, and also the most accurate in the mean. Furthermore, this approach will also give a statistical measure of the scattering of the frequency value. For most practical applications, this mean frequency localized down to quarter of a wave period is already a well-accepted result. As this method physically measures the period, or part of it, the values obtained can serve as the best local mean over the period to which it applies. Through Extrema Sifting, instead of the cubic spline fitting, this invention constructs the upper envelope and the lower envelope by connecting local maxima points and local minima points of the signal with straight lines, respectively, when extracting a collection of Intrinsic Mode Functions (IMFs) from a signal under consideration.

Abstract: A method, apparatus, and system for spectrum analysis. The method, apparatus, and system for spectrum analysis include measuring energy incident at a frequency in a frequency spectrum corresponding to a channel, but not all frequencies in the frequency spectrum, and determining whether the energy measured at the frequency exceeds a valid channel threshold.

Abstract: A full width array spectrophotometer for full width scanning color analysis of color test targets, with one or two substantially linear elongated arrays of closely spaced multiple LED illumination sources of plural different color emissions in a multiply repeated pattern of at least three or four different colors transversely spanning a printer paper path and sequentially illuminated to illuminate a transverse band across a printed sheet moving in the paper path, and a corresponding elongated low cost light imaging bar with a parallel and correspondingly elongated array of multiple closely spaced different color sensitive (three or four rows of color-filtered) photodetectors, which imaging bar is positioned to detect and analyze light reflected from the transverse sequentially illuminated band.

Abstract: In a method of identifying a source of a signal, the signal is recorded and then analyzed in order to determine its spectrum. The method includes the following steps: in parallel with recording the signal, storing parameters significant of the conditions under which the recording is made; after analyzing the signal and determining its spectrum, detecting lines emerging from the background noise of the signal, using a predetermined emergence threshold; comparing each line detected with some or all of a set of signatures of sources identified and inventoried in a database established prior to the recording; and for each line, and where applicable, selecting signatures that may correspond to the line and, as a function of the resulting signature/line pairs, consolidating, resolving ambiguity of, or quantifying the source corresponding to said line.

Abstract: An observation apparatus according to one embodiment can include a timing generating unit (2) that generates a timing signal at a predetermined period. A sampling unit (3) can sample a current observation signal of a power supply current on the basis of the timing signal, and store sampled data in data storing unit (5). A data number adjusting unit (6) can adjust the number of data samples to a number that is a power of two. An arithmetic operating unit (4) can Fourier-transform the adjusted data to generate frequency spectrum results of the current observation signal. In addition, a failure inspection apparatus according to one embodiment analyzes the frequency spectrum of an integrated circuit under observation to determine a failure condition of the integrated circuit.

Abstract: The method implements time-optimized acquisition of special spectra using a scanning microscope, for which purpose the spectrum is subjected to bisecting interval measurements. The method for time-optimized acquisition of special spectra (emission spectra) using a scanning microscope is implemented in several steps. Firstly a complete spectrum to be examined, within which at least one special spectrum (emission spectrum) is located, is split into at least two intervals. The interval in which the intensity lies above a specific threshold is selected. That interval is split into at least two further intervals, and the procedure is continued until the size of the interval corresponds to the lower limit of the scanning microscope's measurement accuracy. The location of the special spectrum in the complete spectrum is defined, and an interval around it is created and is measured linearly.

Abstract: A method for measuring the EIRP (Effective Isotropic Radiated Power) of a satellite downlink carrier signal is performed by or under the control of a processor located, for example, at a technical operations center of a satellite communications company. The processor operates in accordance with a computer program which automatically identifies a carrier frequency corresponding to a customer, measures a level and bandwidth of the downlink signal at the customer carrier frequency, determines a level of a reference carrier signal, compares the level of the downlink signal to the level of the reference carrier signal, and determines EIRP power of the downlink signal based on the comparing step. The measured EIRP value is then compared to an EIRP value contractually assigned to the customer, and the difference determines the manner in which the measured EIRP value deviates from the assigned power.

Abstract: A method for analyzing a multichannel chromatogram is realized for accurately resolving overlapping peaks on a multichannel chromatogram to permit analysis of the composition of a sample.

Abstract: The present invention is directed to a centrifugal pump wherein voltage and current data are detected from voltage and current sensors in the motor controller of a pump motor. A power signal is then generated from the voltage and current data and spectrally analyzed to determine the presence of unwanted harmonics which are indicative of mechanical disturbances in the pump. As such, anomalies resulting from mechanical interference may be detected and a warning flag provided without additional transducers and other instruments on the motor or pump.

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 of detecting a failure in an IC, based on spectrum which is a result of analyzing a frequency of a current running through an IC when a test signal is applied to the IC, including (a) assuming that all ICs under test define a under-test IC set, and testing each one of the ICs in the under-test IC set in a conventional manner; (b) removing ICs judged to be in failure in (a), from the under-test IC set; (c) measuring spectrum of a current supplied from a power source into each one of the ICs in the under-test IC set; (d) calculating both a mean value and standard deviation of the spectrum for the under-test IC set; (e) judging whether an IC is in failure, based on both the mean value and the standard deviation of the spectrum; (f) removing ICs judged to be in failure in (e), from the under-test IC set; and (g) judging the undertest IC set to be in no failure.

Abstract: A method of multivariate spectral analysis, termed augmented classical least squares (ACLS), provides an improved CLS calibration model when unmodeled sources of spectral variation are contained in a calibration sample set. The ACLS methods use information derived from component or spectral residuals during the CLS calibration to provide an improved calibration-augmented CLS model. The ACLS methods are based on CLS so that they retain the qualitative benefits of CLS, yet they have the flexibility of PLS and other hybrid techniques in that they can define a prediction model even with unmodeled sources of spectral variation that are not explicitly included in the calibration model. The unmodeled sources of spectral variation may be unknown constituents, constituents with unknown concentrations, nonlinear responses, non-uniform and correlated errors, or other sources of spectral variation that are present in the calibration sample spectra.

Abstract: A method for segmenting a signal into segments having similar spectral characteristics is provided. Initially the method generates a table of previous values from older signal values that contains a scoring value for the best segmentation of previous values and a segment length of the last previously identified segment. The method then receives a new sample of the signal and computes a new spectral characteristic function for the signal based on the received sample. A new scoring function is computed from the spectral characteristic function. Segments of the signal are recursively identified based on the newly computed scoring function and the table of previous values. The spectral characteristic function can be a selected one of an autocorrelation function and a discrete Fourier transform. An example is provided for segmenting a speech signal.

Abstract: A user interface is presented for a tester that tests a frequency converter having an input port, an output port and a local oscillator port. In a first area, a user can specify frequency for an input signal to be placed on the input port. In a second area, the user can specify frequency for a local oscillator signal to be placed on the local oscillator port. The tester calculates expected frequency values of an output signal on the output port output based on values entered in the first area and the second area.