Abstract: The present invention is a method and apparatus for testing the random numbers generated by a random number generator in real time. A stream of random bits is generated using said random number generator, then the generated random bits undergo a monobit-run length operation in which a plurality of sub-sequences having one of all 0's or all 1's bits in a row is identified. The output of said monobit-run length calculation is applied to an exponential averaging to obtain an average number of occurrences or frequencies for a range of monobit-run lengths. The monobit-run length frequencies are compared to predetermined acceptance ranges, so that if any of the average monobit-run frequency values falls repeatedly outside the predetermined acceptance range more than a predetermined number of times, it is determined that the generated random bits are insufficiently random.

Abstract: A system and methods for assisting a technician in tuning a musical instrument exhibiting inharmonicity, such as a piano. A display informs the technician of one or more beat rates associated with respective intervals of a note being tuned and other notes. A second display informs the technician of the phase difference between the note being adjusted and a reference signal. The note being tuned is detected automatically, thereby allowing the technician to work without constantly touching the system. The wavelengths emanating from the notes are determined accurately, and the corresponding frequencies are tested for their quality before being used in calculations used for providing the information for the displays. A tuning frequency is calculated for each note after measurement of a first note, and the calculation is updated as more measurements are taken. If desired, the technician may visit each note only once in the tuning of the musical instrument.

Abstract: In a method and apparatus for measuring the frequency of a signal by integration of its signal phase, a phase accumulator integrates the signal phase of the signal, at predetermined time intervals. A first intermediate memory reads in a first output value of the phase accumulator after a predetermined first number of time intervals, as well as a second output value of the phase accumulator after a predetermined second number of time intervals. A second intermediate memory reads in the first output value of the first buffer register and multiplies it by a first factor which corresponds to the quotient of the second number of time intervals and the first number of time intervals. A subtracter subtracts the first output value multiplied by the first factor from the second output value; and a divider divides the output value of the subtracter by a second factor.

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 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 system and methods for assisting a technician in tuning a musical instrument exhibiting inharmonicity, such as a piano. A display informs the technician of one or more beat rates associated with respective intervals of a note being tuned and other notes. A second display informs the technician of the phase difference between the note being adjusted and a reference signal. The note being tuned is detected automatically, thereby allowing the technician to work without constantly touching the system. The wavelengths emanating from the notes are determined accurately, and the corresponding frequencies are tested for their quality before being used in calculations used for providing the information for the displays. A tuning frequency is calculated for each note after measurement of a first note, and the calculation is updated as more measurements are taken. If desired, the technician may visit each note only once in the tuning of the musical instrument.

Abstract: Methods and apparatus for predicting tire uniformity, preferably a harmonic component of force variation for a production tire, preferably when operating at a high speed, and also method and apparatus for manufacturing tires and controlling the manufacturing of tires in response to quality control based on a comparison of a production tire's predicted uniformity versus predetermined criteria. A production tire's predicted tire uniformity is determined by a calculation using transfer functions applied to production tire measurement data from factory floor testing equipment which includes a factory floor balance checker and a factory floor tire uniformity machine. The transfer functions are determined by calculations involving a combination of measurements on a tire sample which preferably comprises one or more tires of the same construction as the production tire for which predictions are desired.

Abstract: A method for generating a signal pulse sequence with a predetermined stable fundamental frequency from a sequence of signal pulses whose frequency fluctuates and has the spectral components whose frequency is at least a predetermined multiple of the fundamental frequency. The method includes, feeding the sequence of signal pulses to a digital filter, arranging a passband of the digital filter around the fundamental frequency, blocking, using the digital filter, around a predetermined half the sampling frequency. The method further includes outputting a signed output signal when the digital filter is excited, and generating a clock signal pulse for each change in sign of the output signal.

Abstract: A method to estimate motor speed for extended stabilized rotational control of an induction motor at all speeds including slow speeds. The speed estimator supplies real-time motor control feedback information for a variable speed motor drive controller without a mechanical encoder. The speed estimator is based on an optimized fast orthogonal search algorithm with control of the carrier drive frequency to reduce computation time. The reduced processing time provides for an update rate to the motor controller sufficient to maintain motor stability to near zero the motor rated base speed.

Abstract: A physical quantity at a given position in an analysis space is expressed by using a Poisson's equation, a Green's function and the Green's theorem. The equation thus obtained is substituted into an unknown parameter in the equation, to be expanded into infinite series. Stopping the expansion when the equation is expanded to some degree, the equation can be expressed only with known parameters such as boundary conditions. Through calculating the respective values of integrations included in terms of the series by the Monte Carlo method and adding them up, a physical quantity at a given position can be thereby obtained. Further, by the same method, a parasitic element constant at a given position in the analysis space can be also obtained. With this method, a simulation is achieved for obtaining a physical quantity and a parasitic element constant at a given position in an analysis space, without solving a matrix equation.

Abstract: A method for measuring a frequency f=&ohgr;/2&pgr; of a sinusoidal signal V(t)=Asin(&ohgr;t+&agr;) with an essentially constant amplitude A. Measured values are registered in the form of the instantaneous level of the signal V(t), V(t−h) and V(t−2h)at three points of time separated by a predetermined measuring period h, which corresponds to a measurement frequency fs=1/h.

Abstract: The spectrum of a PCM signal is divided into bands. Combinations of a reference band inclusive of a highest frequency band and another band, one of the reference band and other band being normalized, are checked to identify a combination having a highest spectrum distribution correlation. The spectrum having the same distribution as the spectrum distribution of the reference band contained in the identified combination is scaled along an envelope function and added to a higher frequency side than the reference band to generate an output signal. A presence/absence of high frequency components of a PCM signal is detected. Only if there are high frequency components, the spectrum components are added to generate an output signal.

Abstract: A method of classifying biological elements into functional families includes the steps of representing a characteristic numerically, performing a time-frequency transform on the numeric representation, and identifying biological elements of a common functional family by clusters of data having a common frequency characteristic in the time-frequency domain. Biologically active regions on those biological elements are identified by an amplitude analysis of the clusters.

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: A method for detecting the resonance frequency of an electrical oscillation circuit, in particular that of a starter oscillation circuit for high-pressure gas discharge lamps, is described in which the oscillation circuit is excited with various frequencies. The frequency search is undertaken in a search run with individual search attempts. A specific, fixed frequency is used for the sampling tests. Each fixed frequency is selected and used according to a specific search pattern. In the search pattern, the first sampling test is carried out with the mean frequency, which is the mean between the minimum and maximum possible resonance frequencies. In each of the subsequent sampling tests, the test frequency is modified in steps. The resonance frequency found in a search run can be stored as a learning frequency for use as a starting frequency for subsequent search runs and updated as necessary.

Abstract: A noise injection method for characterizing common clock timing margin (jitter) is disclosed. The method includes the steps of injecting a single tone frequency, varying the amplitude of the injected frequency; measuring the signal produced at various signal amplitudes and analyzing the data obtained from measuring the signal. The measurements obtained may be analyzed using various characterizations such as measured jitter on input, measured jitter transfer, measured jitter tolerance etc.

Abstract: A method of compensating periodic error signals in sensor output is provided. The method comprises obtaining a sum signal from sensing outputs of M sensor elements (where M is a positive integer), obtaining the amplitude and phase of N frequency components included in the sum signal, and calculating a sensing output gain adjustment coefficient for each sensor output. To ensure that a sum signal level obtained by summing a pre-adjustment output of each sensor element multiplied by the gain adjustment coefficient equals a sum signal level obtained by summing the unmodified outputs of the sensors, a gain adjustment coefficient is obtained for each sensor output by using a calculated scaling coefficient to perform pre-adjustment scaling of each gain adjustment coefficient. The adjustment gains thus obtained are used to adjust the gain of each sensor output.

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: The present invention relates to a method of determining a speed of rotation of a squirrel-cage motor, in which method samples from the current taken by the squirrel-cage motor are collected by an electric current measuring device at a predetermined sampling frequency for a measurement period, the samples being stored as measurement data of a fixed format. The method is characterized by comprising the step of determining the rotation speed of the squirrel-cage motor from the measurement data by determining the base frequency and side frequencies of the electric current taken by the squirrel-cage motor, the rotation speed frequency of the squirrel-cage motor being obtained by subtracting the lower side frequency from the higher side frequency and by dividing the difference thus obtained by two.

Abstract: A system and methods for assisting a technician in tuning a musical instrument exhibiting inharmonicity, such as a piano. A display informs the technician of one or more beat rates associated with respective intervals of a note being tuned and other notes. A second display informs the technician of the phase difference between the note being adjusted and a reference signal. The note being tuned is detected automatically, thereby allowing the technician to work without constantly touching the system. The wavelengths emanating from the notes are determined accurately, and the corresponding frequencies are tested for their quality before being used in calculations used for providing the information for the displays. A tuning frequency is calculated for each note after measurement of a first note, and the calculation is updated as more measurements are taken. If desired, the technician may visit each note only once in the tuning of the musical instrument.

Abstract: Apparatus for determining the frequency of an ac power signal, includes sensing circuitry to sense the ac signal. In a digital implementation of the invention, a double average of the samples is generated by a processor as the sum of the most recent sample, twice the next most recent sample plus the third most recent sample. The least mean square of a running window of the most recent double average signals is generated to avoid discontinuities at the zero crossings and to reduce the effects of noise. The frequency is determined from this least mean square value of the window of double average signals. As implemented in a protective relay, a trip signal is generated if the frequency is out of limits.

Abstract: A technique for computing RMS values for sampled waveforms. More specifically, a technique for computing RMS values for periodic waveforms, using data taken from a full waveform, a half waveform or some other portion of a waveform is described. Each RMS calculation is based on a different algorithm and provides accurate, real time data.

Abstract: A direct current machine monitoring system includes a current sensor for monitoring load current of the machine; and a computer for obtaining a power spectrum in a range including a machine trait-passing frequency, determining a magnitude of a maximum peak in the power spectrum in a range including the trait-passing frequency plus or minus an uncertainty frequency, and evaluating the magnitude of the maximum peak to assess a condition of the machine. The computer may additionally or alternatively be used for obtaining a low frequency power spectrum of the load current, obtaining at least one magnitude of a component of the power spectrum at a respective predicted frequency, and evaluating the at least one magnitude of the component to assess the condition of the machine.

Abstract: The damping behavior of a physical system is evaluated by mapping of damping loss factors calculated from time-dependent amplitude and frequency functions to form a full time-frequency dependent damping spectrum. The time-dependent amplitude and frequency functions are formulated by calculations based on the intrinsic mode functions derived by empirical mode decomposition of the original time series dataset representing the system behavior. The amplitude and frequency functions for each intrinsic mode function are calculated from the polar representation of the Hilbert transform-based time-dependent complex function corresponding to the intrinsic mode function.

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: A system and method (and storage media) for identifying the category of the source noise and sound by using the physical factors derived from the autocorrelation function (ACF) and the interaural crosscorrelation function (IACF) which are ever changing in the time domain based on the model of human auditory brain function system. A method for evaluating a sound comprises the steps of: using the sound recorder to capture and record the acoustic signal; calculating the ACF from the acoustic signal using a CPU; calculating ACF factors extracted from the calculated ACF using the CPU; and identifying the kinds of the noise based on the ACF factors. Thereby the unknown noise source can be identified what it is (such as automobile noise, and factory noise), and can be identified its type such as type of cars or type of machines.

Abstract: A system and method for analyzing order components present in a physical signal X acquired from a physical system. Measurement information for the physical signal X may be received, where the measurement information includes information indicating a plurality of order components of the physical signal X. Time frequency plot information visually indicating order components of the physical signal X may be displayed. User input selecting one or more of the visually indicated order components may be received. A time domain signal may be created based on the one or more selected order components and may then be presented to a user on a presentation device. Presenting the time domain signal on the presentation device may enable the user to analyze the physical signal X or the physical system. Where the physical system includes one or more rotating elements, the method may enable order components of the signal to be analyzed even when no rotation speed information (e.g.

Abstract: A method for calibrating an instrument includes maintaining typical response values at respective frequency locations. The response of the instrument being calibrated is measured at a subset of frequency locations in the typical response. Response values for frequency locations not in the subset are estimated from the typical and measured response values. The instrument is calibrated based on the actual and estimated response values. Apparatus for calibrating an instrument includes a signal generator, coupled to the instrument, which generates a signal having known characteristics. A controller, coupled to the instrument, generates a calibration signal. Controller memory stores typical response values at respective frequency locations, and measures response values at a subset of the frequency locations. Response values for frequency locations not in the subset are estimated from the typical and measured response values. The instrument is calibrated in response to the measured and estimated response values.

Abstract: Methods and apparatus for predicting tire uniformity, preferably a harmonic component of force variation for a production tire, preferably when operating at a high speed, and also method and apparatus for manufacturing tires and controlling the manufacturing of tires in response to quality control based on a comparison of a production tire's predicted uniformity versus predetermined criteria. A production tire's predicted tire uniformity is determined by a calculation using transfer functions applied to production tire measurement data from factory floor testing equipment which includes a factory floor balance checker and a factory floor tire uniformity machine. The transfer functions are determined by calculations involving a combination of measurements on a tire sample which preferably comprises one or more tires of the same construction as the production tire for which predictions are desired.

Abstract: A method and an apparatus for measuring the instantaneous frequency of FM modulated signals, includes sampling, instantaneous frequency computing, and lowpass filtering. FM modulated signal are sampled at prescribed intervals to provide digitized FM signal. The instantaneous frequency is computed by manipulating the digitized FM signal mathematically using a new mathematical equation proposed in this invention to provide the instantaneous frequency based on digitized FM signal samples. More accurate instantaneous frequency values can be obtained by filtering the computed instantaneous frequency values using a lowpass filter.

Abstract: The start up performance of an ultrasonic system under zero load conditions is improved by setting a phase set point in a frequency control loop such that, at start up under zero load conditions, the phase set point intersects a point on a phase-frequency response curve which has a low positive slope. This intersection point on the phase-frequency response curve changes as the load is increased and the system Q is decreased. The controller “seeks” a target 0° impedance phase angle. The frequency of the ultrasonic generator is set to an off-resonance frequency which is lower than the resonance of any known hand piece/blade combination. In order for the drive voltage to not exceed the physical limit of the system, the drive current is set to a low level. The drive frequency is then smoothly increased in steps until the target 0° impedance phase delta is located.

Abstract: An ultrasonic surgical hand piece is caused to be driven with an output displacement that is correlated with the phase margin, which is the difference of the resonant frequency and the anti-resonant frequency of the hand piece. A frequency sweep is conducted to find the resonant frequency and the anti-resonant frequency for the hand piece. The resonant frequency is measured at a point during the frequency sweep where the impedance of the hand piece is at its minimum. The anti-resonant frequency is measured at a point during the frequency sweep where the impedance of the hand piece is at its maximum. Using a target or specific output displacement, a drive current is calculated based on the phase margin which is the difference between the resonant frequency and the anti-resonant frequency. The hand piece is caused to be driven with the output displacement, by accordingly controlling the current output from a generator console for driving the hand piece.

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: A method, system, and apparatus for a timing subsystem in a radio frequency identification tag device are described. The timing subsystem provides a system oscillator or clock for the tag. The timing subsystem also provides frequencies used by an RF interface of the tag to generate backscatter modulated symbols. The timing subsystem also provides for oscillator calibration. The tag receives one or more oscillator calibration waveforms transmitted by a reader. The timing subsystem in the tag uses the oscillator calibration waveforms to successively adjust the frequency of the tag oscillator to a frequency desired by the reader. Hence, the reader may increase or decrease the oscillator frequency in the tag depending on the particular application. Furthermore, the reader may adjust the oscillator frequency for all tags in a population of tags using a single transmission of the one or more oscillator calibration waveforms.

Abstract: Circuitry for detecting tonal signals, each of which has a particular nature in the frequency or time domain, while distinguishing them from each other. A rough frequency analyzer roughly analyzes an input signal in an entire frequency band with lower accuracy in the frequency or time domain, thereby roughly distinguishing the tonal signals. Detectors, each of which is associated with a subband occupied by a particular target tonal signal, detect the attribute of the power variation of the target tonal signal with respect to time with higher accuracy in the direction of the frequency or time domain to thereby finely identify the target tonal signal. A controller selectively enables and disables the detectors in accordance with the results from the detectors. One of the detectors is enabled which is selected under the control of the controller.

Abstract: The present invention is a method and apparatus to detect an instantaneous frequency of an input signal. A sampler samples the input signal to generate a sampled signal. A metric generator is coupled to the sampler to generate a metric signal based on the sampled signal. The metric signal has a magnitude proportional to the instantaneous frequency of the input signal. In another embodiment, the apparatus comprises a feedback circuit and a decimator. The feedback circuit generates a sequence signal from the input signal. The sequence signal represents a change of the instantaneous frequency of the input signal. The decimator is coupled to the feedback circuit to decimate the sequence signal to generate a frequency signal. The frequency signal providing the instantaneous frequency of the input signal.

Abstract: A fingerprint of an audio signal is generated based on the energy content in frequency subbands. Processing techniques assure a robust identification fingerprint that will be useful for signals altered subsequent to the generation of the fingerprint. The fingerprint is compared to a database to identify the audio signal.

Abstract: A method and apparatus for detection of missing pulses from a repetitive pulse train including signal detection circuits for capturing the rising and/or falling edges of an input signal, time-stamping the captured edges, calculating the maximum and minimum instantaneous frequency over a specified time period, and displaying such frequency values. Instantaneous frequency values between any two adjacent edges are calculated based upon the time-stamps of the edges. The instantaneous frequency values in a specified time period are then sorted to find the minimum and maximum frequency values for that time period. These instantaneous frequency values are displayed in the form of a histogram evidencing the occurrence or lack of occurrence of missing pulses from the input signal.

Abstract: A technique for measuring the current, voltage and phase of a Radio Frequency (RF) power wave to an RF load, accounts for the finite length of the voltage and current pickups, and corrects for effects of standing wave components of voltage and current. Voltage and current are computed as complex functions of the voltage pickup signal and the current pickup signal, based on coefficients precalibrated for the predetermined radio frequency. Alternatively, a corrected current value can based on the corrected voltage value and complex load impedance. The correction coefficients can be obtained, for each of a plurality of calibrating radio frequencies within an RF range, from voltage and current pickup signals under conditions of (a) open circuit load, (b) short circuit load, (c) fixed known impedance load; and (d) one of voltage and current being applied at a precise input level to a known load from an RF calibration source.

Abstract: A gait detection apparatus includes a microphone for picking up low-frequency-band sounds which are transmitted through the body of a pedestrian while walking and an analyzer for performing analysis. Accordingly, the gait of the pedestrian is detected. It is also possible to distinguish the gait pattern on the basis of the stance-phase time of a foot sole, the signal intensity, etc. The gait detection apparatus can accurately estimate the step length on the basis of a detected gait cycle, the height of the pedestrian, and signals detected during walking. On the basis of low-frequency-region sounds picked up by the microphone while the pedestrian is walking, the pedestrian can be identified.

Abstract: A process for obtaining the periodic component in a data vector of data taken of a sensed property of an element driven by one or more rotary components over several rotations. The procedure comprises first forming the data vector asynchronously with respect to rotation of said one or more rotary components. A series of marker signals representing the rotation of the one or more rotary components is also established. From these the periodic component of data in said data vector is determined as a function of the data in the data vector and the marker signals.

Abstract: A signal transfer device measurement system and method of the present invention measures the signal transfer characteristics of a device under test (DUT) having an analog input port and either an analog output port or a digital output port. The measurement system and method comprise a stimulus waveform generator that produces a stimulus waveform. The stimulus waveform comprises a time sequence of pairs of narrow bandwidth, modulated signals. The stimulus waveform is applied to the input port of the DUT thereby producing an output response signal at the output port of the DUT. For a DUT with an analog output port, the measurement system and method further comprise an analog-to-digital converter (ADC) for digitizing the output response signal and producing digital data and a signal processor for processing the digital data thereby producing measured results.

Abstract: An extremely low frequency (ELF) receiver that operates at the 6 Hz to 9 Hz range to synchronously receive signals from the electric (E) field or the magnetic (H) field of the earth's resonant (TS) frequency and other signals of interest.

Abstract: A method and apparatus for characterizing frequency response of a device (DUT) is disclosed. A repeated base bit pattern is received, the base bit pattern including a first transition from a 0-bit to a 1-bit. Then, using bit error rate distribution, multivalue voltage along the first transition is determined. Finally, the multivalued voltages are converted into frequency domain using fast Fourier transform. The apparatus includes a processor and storage with instructions for the processor to perform these operations. Using the present inventive technique, the frequency response of the DUT can be determined using an error performance analyzer such as a BERT.

Abstract: A new correlation process and implementing apparatus for use in detecting the presence and location of a concealed eavesdropping device is disclosed in the present application. The process correlates a demodulated intercepted signal with a reference signal that corresponds to the sounds present in an environment of interest. A high correlation between the demodulated intercepted signal and the reference signal indicates that the demodulated intercepted signal corresponds to the audio in the environment of interest. An improved Correlation process is implemented using Fast Fourier Transforms to calculate a figure of merit based upon correlation data determined from sampled versions of the reference and intercept signals. The improved process and apparatus further provides a range to the detected surveillance device and multiple range measurements may be used to triangulate on the surveillance device to determine its precise location.

Abstract: A method for operating a spectrum analyzer to provide a marker that follows a peak from sweep to sweep in a spectrum display. The method operates on first and second measured spectrums. The first measured spectrum includes a plot of the signal amplitude against frequency during a first time interval in which the marker has been assigned to a peak at a first frequency and first amplitude. The present invention assigns the marker to a peak in the second spectrum measured during a subsequent time interval in which the marker is to be assigned. Initially, a first frequency range is defined in the second measured spectrum centered on the first frequency. The first frequency range is searched for candidate peaks having amplitudes within a first range centered on the first amplitude. If more than one such candidate peak is found by the search, the marker is assigned to the candidate peak closest to the first frequency.

Abstract: An apparatus and method to characterize an input communication signal as being a voice, tone or noise signal is provided. The apparatus and method involve measuring variations of pitch over time from a sampled input signal. A minimum value of Average Magnitude Difference Function (AMDF) over a pitch range and an average variation value of the AMDF over sampled intervals are used to determine whether the signal is a voice signal, a tone or noise. Historical data of these values is maintained in a dual buffer arrangement and is used in the determination of signal type by detecting transitions.

Abstract: A frequency analyzing device for detecting a signal component of a predetermined analytic frequency to be analyzed in an input signal includes a multiplication circuit and an integration circuit. The multiplication circuit controls a switched capacitor circuit for discretely storing an input signal using a predetermined pulse signal whose frequency changes according to an amplitude of an orthogonal function system signal having the analytic frequency, and outputs charges representing a multiplication result of the input signal and the orthogonal function system signal. The integration circuit integrates the charges output from the multiplication circuit and outputs integration values as signal components of the analytic frequency contained in the input signal.

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 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.