Abstract: A method according to the present invention calculates a performance function for a structural system (10) that can be used to determine system dynamics at points of interest on the structural system (10). A test input force is applied to an input subsystem (12) and an output subsystem (14) while the motion in response to the test input force is measured to determine a drive point transfer function. A test relative force is applied to the input subsystem (12) and output subsystem (14) at interface points in all degrees of freedom while the motion in response to the test relative force is measured in all degrees of freedom to determine the interface transfer functions. A performance function for the structural system (10) is mathematically calculated based upon the measured drive point transfer functions and interface transfer functions.

Abstract: This invention determines whether two logic level circuit models have equivalent functionality. The method allows difficult portions of the equivalent functionality check to be partitioned and concurrently solved in a distributed computing environment. This permits the user to use, in a scalable fashion, additional computing resources to rapidly solve difficult equivalent functionality checks. The method allows difficult checks to be solved using (1) a divide-and-conquer approach, (2) by a competitive approach in which many independent attempts are made to solve the same check, or (3) by allocating more resources to solve the difficult check.

Abstract: A thorough error suppression signal measurement system (20) having a transmitter (300) for propagating a transmission signal to a first probe 100, through a device under test (26), and into a second probe (200), and for propagating reference signals to the probes (100,200). The probes (100,200) extract normalization signals from the reference signals, exchange specific ones of the normalization signals, and combine the normalization signals with data signals derived from the transmission signal to form receiver signals. The probes (100,200) propagate the receiver signals to a receiver (400), where the signals are gain-ranged, digitized, normalized, and compensated for phase-noise.

Abstract: A method for extending dynamic range and a test system with extended dynamic range compensate for a compression effect on measured data caused by a receiver channel of the test system being compressed. The measured data is magnitude and phase data for one of a device under test and a signal under test that is measured using the test system. The method comprises characterizing a first channel of the test system for first channel compression responses to magnitude and phase, characterizing a second channel of the test system for second channel compression response to magnitude and phase, and compensating to correct for the effect of compression on the measured data. The test system comprises a receiver channel, and a computer program stored in memory that implements the method. Test systems with a plurality of receiver channels may be characterized in pairs.

Abstract: A method for analysis of the time response of complex distributed systems with basic components (B) which have data processing program modules and/or electronic circuit modules, having the following steps:

Abstract: A method for facilitating field replacement of sensors is presented. The replacement sensor's transfer function need only be measured, not adjusted, and the signal-processing unit's transfer function need only be adjusted, but not measured, to achieve simple field-replacement of sensors. With this method simple calculations and adjustments, typically expedited by means of a computer program, can be made in the field when sensor replacement is required. By way of the presently disclosed method sensor cost and size are not increased since no normalization techniques or components are required.

Abstract: A method for determining the desired decoupling components for stabilizing the electrical impedance in the power distribution system of an electrical interconnecting apparatus, including a method for measuring the ESR for an electrical device, a method for determining a number of desired decoupling components for a power distribution system, and a method for placing the desired decoupling components in the power distribution system. The method creates a model of the power distribution system based upon an M×N grid for both the power plane and the ground plane. The model receives input from a user and from a database of various characteristics for a plurality of decoupling components. The method determines a target impedance over a desired frequency range. The method selects decoupling components. The method determines a number for each of the decoupling components chosen. The method places current sources in the model at spatial locations corresponding to physical locations of active components.

Abstract: The invention is a method of measuring transfer functions of a physical system using a wideband excitation signal by exciting the system with a low-power, wide band input signal that has a rich frequency content over a wide band and using a stochastic process to derive a system transfer function over the excitation signal bandwidth.

Abstract: A method is provided for quickly determining low threshold voltages and high threshold voltages of a test circuit. Specifically, a transformed voltage transfer curve for the test circuit is generated. The maximum and minimum points of the transfer circuit are determined to calculate transformed voltage threshold values. The transformed voltage threshold are transformed to find the desired threshold voltages.

Abstract: A modal analysis method and apparatus for acoustically determining dynamic vibration characteristics of a structure, including natural frequencies, mode shapes and damping factors, is based on a Multiple-Input-Single-Output (MISO) model. The method and apparatus involve generation of an acoustic excitation signal toward n spatially distributed locations associated with the structure while the latter is held to allow vibration thereof, one of the locations being chosen as a reference location. A series of microphones are disposed at the locations to produce m complementary sets of n input acoustic pressure-related electrical signals, one of these being chosen as a reference signal associated with the reference location. A Fourier analysis is performed on the sets of input acoustic pressure-related electrical signals to provide corresponding sets of correlated input acoustic pressure-related data in the frequency domain including reference data associated with the reference signal.

Abstract: Systems and methods for designing or determining parameters for a system are disclosed. These systems and methods exploit the Tensor Convolution Block Toeplitz (TCBT) structure involved in certain systems wherein a symmetric positive definite linear system of equations needs to be solved in the design or determination of the parameters for the system. Further, these methods and systems employ a TCBT-PCG process that uses a fast matrix-vector multiply in order to improve the computational efficiency in the design or determination of these system parameters.

Abstract: A method for setting the trigger power of transmitter diodes that transmit data via optical paths allows the transmission power to be adjusted and adapted to the communication distance. The trigger power is determined for the present communication distance on the basis of a test signal before data transmission begins. A circuit arrangement implementing the method includes a driver circuit with a switching device that switches a circuit junction point selectively to a supply voltage or to a constant reference voltage, a voltage-controlled resistor which delivers the driver current and is controlled from the circuit junction point, and a voltage-controlled measuring resistor which delivers a measured current with a fixed relationship to the driver current and is controlled from the circuit junction point. Since the set trigger power can be reduced, the power consumption for data transmission can be reduced considerably.

Abstract: A method for providing a mathematical expression representing the operation of a field-effect transistor in its saturation region is disclosed. Data representing the operation of the transistor is divided into data segments with a monomial function fitted to each of the segments. The data segments are selected for a particular operating parameter such as transconductance based on knowledge of the transistor operation. The error at the transition from one function to another is checked and the data segments redivided to minimize the error. The resulting expression lends itself to global solution with geometric programs.

Abstract: An apparatus and method for estimating one or more pole frequencies of an amplifier circuit, such as a readback signal amplifier circuit implemented in an arm electronics module of a data storage system, are disclosed. A bias signal that biases the read transducer is modulated at first and second modulation frequencies while a readback signal is obtained from a data storage medium using the read transducer. The readback signal is communicated to the amplifier, and an output signal of the amplifier circuit is measured at the respective first and second modulation frequencies. The amplifier pole frequency is determined by computing a square impedance measurement ratio using square magnitudes of the bias signal and the amplifier output signal respectively measured at the first and second modulation frequencies.

Abstract: A measuring system for measuring a transfer function matrix of a system to be controlled by applying sine-wave excitations to a test object simultaneously by multiple number of vibrators. In the measuring system, when sine-wave signals for driving multiple number of vibrators are generated, phases between the sine-wave signals are shifted randomly, first, and then multiple number of vibrators are excited simultaneously under the generated sine-wave signals. Then, an auto-spectrum and a cross-spectrum for one calculation are calculated from spectral data on a vibration frequency obtained from an analysis of excitation signals and response signals acquired during the excitations.

Abstract: An improved interface is established between a field management system and a calibrator for calibrating a process device to provide increased efficiency. The interface includes a communication module for communicating with the calibrator in accordance with a calibrator-specific protocol and a translation module for translating calibration information between an FMS-compatible format and a common data format. The interface allowing calibration information to flow between the calibrator and the FMS.

Abstract: An application specific automated test equipment system for source synchronous bus interface devices is described. A native interface board is provided to interface an automated test unit and a device under test. The native interface board is configured with devices selected to recreate a native environment of the device under test. A first clock drives the devices on the native interface board. A second clock drives the device under test. The second clock signal is derived from the first clock signal to form a substitute clock signal that can be adjusted in relation to the first clock signal. Input and output timing relationships of the device under test are determined by altering the arrival time of the substitute clock at the device under test with respect to the timing of the first clock signal.

Abstract: An equivalence checking system and method efficiently determine whether different circuit models are functionally equivalent. The equivalence checking system first verifies the functional equivalence of a first circuit model to a second circuit model. In verifying this equivalence, the equivalence checking system produces mapping point pairs. The equivalence checking system utilizes these mapping point pairs in determining whether other models of the circuit are equivalent to the first model. Since the mapping point pairs are reused by the equivalence checking system, the number of new mapping point pairs needed to verify the functional equivalence of the other models is reduced or eliminated. Accordingly, the overall efficiency of the equivalence checking system is increased.

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

Abstract: An apparatus and method for determining a transducers principle operating parameters which utilizes two transfer functions; 1) the transfer function from the pressure response (50) to the voltage drop across the transducer (60); and 2) the transfer function from the pressure response (50) to the current flow through the transducer(70). The parameters of simple filter equations are fitted to these measured response curves. The transducers operating parameters are then calculated directly from the fitted parameters of the filter equations. Several methods for measuring the pressure and determining the appropriate filter equations are shown.

Abstract: A multiconductor continuity and intermittent fault analysis system that subjects the cable to controlled environmental stress stimuli, such as vibration at a plurality of frequencies simultaneously, during testing. Multiconductor cables used for the transmission of digital data and control signals include multiple individual conductors terminating at both ends in pins or sockets that are grouped together in a connector. Physical defects in these cables can be permanent, or they can be intermittent faults, such as temporary breaks or shorts caused by vibrational stress on the cables. By vibrating the cable under test and measuring continuity rapidly enough to detect short-term anomalies, even intermittent faults are located. A distributed processing embodiment disclosed uses a user interface unit such as a personal computer or personal digital assistant, a multiprocessor controlled control unit, and the dynamic stimulation unit.

Abstract: An unsteady signal analyzer for detecting a defect in a monitored object through the analysis of an unsteady signal generated by the monitored object has a wavelet transform calculating device which produces a wavelet spectrum data through a wavelet transform of the unsteady signal, a state variation function setting device which sets a state variation function representing a variation of a specific state variable of the monitored object with time, and a time coordinate nonlinear transformation device which transforms a time coordinate of the wavelet spectrum data nonlinearly into a coordinate of the specific state variable by using an inverse function of the state variation function.

Abstract: For conversion of spectral information of an FTIR spectrometric instrument for comparison with that of a dispersion instrument, a first standard function is selected for spectral line shape for the first instrument, and a second standard function for line shape is selected for the second instrument. A conversion factor is computed for converting the first standard function to the second standard function. In ordinary operations, first spectral information is obtained with the first instrument for a first sample, and second spectral information is obtained with the second instrument for a second sample. The conversion factor is applied to the first spectral information to effect converted information, and the converted information is compared with the second spectral information. Such conversion also is applied between chromatographic instruments.

Abstract: A method and apparatus are described for fusing a plurality of signals, corresponding to mean and covariance estimates, into a single signal when the given signal estimates are correlated to an unknown degree. The core components of the method and apparatus are (1) capability to express the means and covariances of the set of signals in inverse form in a common coordinate frame and (2) capability to form a signal determined by a convex combination of the means and covariances, so expressed. The set of estimates to be fused may comprise previously fused estimates as well as measurements of a physical system. The signal derived from the fused result can be transmitted and used to physically respond to the measured state of the system of interest.

Abstract: The phase response of a network is measured at uniform frequency intervals. A linear regression analysis is performed on samples of the phase response measured at frequencies within an aperture centered on a group delay frequency to obtain an estimate of the group delay of the network at that frequency. The process is repeated for a sequence of group delay frequencies to determine a trace of the group delay of the network across a range of frequencies.

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

Abstract: A system and a method for estimating the mean and covariance resulting from the application of a given nonlinear function or transformation when applied to a given mean and covariance derived from measurements of a physical system or process. The method comprises selecting a set of points having an arbitrary mean different from the given mean, but with covariance about the given mean equal to that of the given covariance; applying the given nonlinear function to each element of the selected set of points; computing an estimate of the mean of the nonlinearly transformed given mean and covariance; and computing the covariance of the nonlinearly transformed set of points about the estimated mean. The system and method provide an efficient procedure for accurately incorporating nonlinear models of quantities of interest in tracking systems, control mechanisms, and many other related signal processing systems.

Abstract: A test mode circuit for use in a data system includes a test mode code latch for receiving a test mode code. A switch, which when turned on, couples the test mode code latch to the input so that the test mode code can be transferred from the input to the test mode code latch. A test mode command decoder is coupled to the test mode code latch for decoding the test mode code to initiate a test mode of operation in the data system. A data storage unit is coupled to the test mode command decoder for storing a data bit which corresponds to a low voltage test mode enable signal. The data bit may be modified during the test mode of operation. A low voltage test mode circuit is coupled to the data storage unit which, after first being enabled by the low voltage test mode enable signal, can be controlled to turn the switch on and off. An enable signal generation circuit couples the low voltage test mode circuit to the switch for turning the switch on and off.

Abstract: A rotary position transducer comprises a sensor cooperating with a toothed wheel which has nominally evenly spaced teeth and which may, for instance, be mounted on the crankshaft of an internal combustion engine. The times at which the teeth pass the sensor are stored. The time intervals between consecutive teeth are calculated, for instance during fuel cut-off operation of the engine. An error in the angular spacing between consecutive teeth is calculated for the time interval between consecutive teeth, a time interval between further teeth disposed symmetrically about the consecutive teeth, and the nominal angular spacing between the further teeth.