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Instrumentation and Measurement, IEEE Transactions on

Issue 3 • Date June 2004

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Displaying Results 1 - 25 of 40
  • Table of contents

    Page(s): c1 - 621
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    Freely Available from IEEE
  • IEEE Transactions on Instrumentation and Measurement publication information

    Page(s): c2
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  • New digital signal-Processing approach for transmitter measurements in third generation Telecommunications systems

    Page(s): 622 - 629
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB) |  | HTML iconHTML  

    The rapid growth of third generation (3G) telecommunications systems has created the need for getting new test equipment as well as getting measurement techniques up and running in a very short time. Trying to satisfy this exigency, a new measurement method for testing 3G transmitters is proposed here. Thanks to the use of time-frequency distributions, the method provides a unified approach for carrying out, automatically and in a very straightforward manner, most measurements needed to fulfill the aforementioned task. After a brief outline of 3G technology basics, some details concerning transmitter tests are given. The fundamental steps of the proposed method are then described with references to a clarifying example, also highlighting advantages with respect to other measurement solutions. At the end, the performance of the method is assessed by means of several experiments on both simulated and emulated signals. View full abstract»

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  • Neuro-fuzzy TSK network for calibration of semiconductor sensor array for gas measurements

    Page(s): 630 - 637
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    The neuro-fuzzy network applying Takagi-Sugeno-Kang (TSK) fuzzy reasoning for the calibration of the semiconductor sensor array is developed in this paper. The structure, as well as the learning algorithm of the neuro-fuzzy network, is presented and tested on the example of estimation of the concentration of gas components in the gaseous mixture (so-called artificial nose problem). The results of numerical experiments are presented and discussed. View full abstract»

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  • Neuro-fuzzy network for flavor recognition and classification

    Page(s): 638 - 644
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    This paper presents the neuro-fuzzy Takagi-Sugeno-Kang (TSK) network for the recognition and classification of flavor. The important role in this process fulfills the self-organizing process used for the creation of the inference rules. The self-organizing neurons perform the role of clustering data into fuzzy groups with different membership values (the preprocessing stage). Applying the automatic control of clusters, we have the optimal size of the TSK network. The developed measuring system has been applied for the recognition of flavor of different brands of beer. The fuzzy neural network is used for processing signals obtained from the semiconductor sensor array. The results of numerical experiments have confirmed the excellent performance of such solutions. View full abstract»

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  • Finite sample properties of ARMA order selection

    Page(s): 645 - 651
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    The cost of order selection is defined as the loss in model quality due to selection. It is the difference between the quality of the best of all available candidate models that have been estimated from a finite sample of N observations and the quality of the model that is actually selected. The order selection criterion itself has an influence on the cost because of the penalty factor for each additionally selected parameter. Also, the number of competitive candidate models for the selection is important. The number of candidates is, of itself, small for the nested and hierarchical autoregressive/moving average (ARMA) models. However, intentionally reducing the number of selection candidates can be beneficial in combined ARMA(p,q) models, where two separate model orders are involved: the AR order p and the MA order q. The selection cost can be diminished by creating a nested sequence of ARMA(r,r-1) models. Moreover, not evaluating every combination (p,q) of the orders considerably reduces the required computation time. The disadvantage may be that the true ARMA(p,q) model is no longer among the nested candidate models. However, in finite samples, this disadvantage is largely compensated for by the reduction in the cost of order selection by considering fewer candidates. Thus, the quality of the selected model remains acceptable with only hierarchically nested ARMA(r,r-1) models as candidates. View full abstract»

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  • Noncoherent spectral analysis of ADC using filter Bank

    Page(s): 652 - 660
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB) |  | HTML iconHTML  

    The aim of this paper is to propose a new spectral analysis method for an on-chip analog-to-digital converter (ADC) dynamic test. ADC characterization by spectral analysis has traditionally been done with discrete Fourier transform. This method imposes restrictions to optimize results; one of these is coherent sampling. Recently, some filter structures have been used for spectral analysis of a sinusoidal signal corrupted by harmonics and noise. In this paper, we present a new filter bank structure used for decomposing a signal into its main spectral components. The main application examined is ADC spectral parameter estimation, like signal-to-noise and distortion ratio, signal to noise ratio, total harmonic distortion, and so on, in noncoherent sampling. Computer simulations are used to demonstrate the performance of the proposed filter bank scheme. This structure is a promising built-in self-test (BIST) approach for ADC ICs. View full abstract»

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  • Using a CCD camera for the determination of the target size in radiation thermometry

    Page(s): 661 - 664
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB) |  | HTML iconHTML  

    The objective of this paper is to present the new objective method for the determination of the target size in radiation thermometry using a charge-coupled device (CCD) camera and the custom-made software. The target size is one of the essential components needed for the proper calibration of a radiation thermometer, as well as for everyday measurements. In practice, most of the radiation thermometers have a small black ring engraved on the ocular, and the interior of the ring defines the target area. Usually, manufacturers state how much radiation is gathered from the target area. Typical values stated are from 90% to 99%. The existing method was very subjective. A person determining the target size looked through the radiation thermometer and tried to read the target size of the thermometer from the millimeter grid paper. In our case, three different people in our laboratory, using this existing method, determined different target sizes. The new method uses a predefined mask of known dimensions, printed on millimeter grid paper and positioned in front of the radiation thermometer. Instead of a person looking through the ocular, a CCD camera and the custom-made image processing software are used. This target size can be used as an indication of target size in cases when other information is unavailable or to check manufacturer's data. View full abstract»

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  • A DSP-based mixed-signal waveform generator

    Page(s): 665 - 671
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    As it currently stands, waveform generators are being employed in many diverse areas, such as radar applications, communication systems, simulation, and testing. There is considerable interest in exploring the beacon of opportunity posed by using digital signal processor (DSP)-based systems to replace costly and inadequate conventional waveform generators. The availability of high performance DSPs allows for the design of highly flexible equipment capable of real-time processing. The arbitrary waveform generator introduced in this paper consists of a DSP, a FIFO memory, a video palette, and a PC interface. A program running on the PC creates a digital representation of a waveform according to user parameters and sends it to the DSP's RAM. The DSP algorithmically converts the digital representation to a point-by-point representation of the desired analog signal. The data points are sent to the FIFO buffer, which latches the data to a video palette that serves a three-channel digital-to-analog converter. The system employs a high-speed serial port interface to communicate with a PC, to allow for readily programmed signals. In addition to the production of traditional signals, such as sinusoids and squarewaves, a mathematical tool known as splines is employed to aid in the development of customized arbitrary waveforms. Finally, a picture of our new device is presented in the paper. View full abstract»

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  • Auto-evaluation of the uncertainty in virtual instruments

    Page(s): 672 - 677
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB) |  | HTML iconHTML  

    A numerical approach based on a Monte Carlo probabilistic method is used as an advantageous alternative to the traditional analytical methods for the evaluation of the uncertainty in measurements achieved by digitally processing sampled input data. The correctness of the approach is shown in the case of both single-channel and multichannel systems. Some practical concerns about the reliability of the proposed methodology are discussed, and suitably designed virtual instruments are presented that are able to present the measurement result along with its uncertainty. View full abstract»

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  • A biaxial probe for nondestructive testing on conductive materials

    Page(s): 678 - 684
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    A biaxial probe for nondestructive testing on conductive materials was set up and tested. Its behavior was investigated at first by using a dedicated simulation environment. Then experimental tests confirm the simulation results and allow better highlighting of the probe effectiveness. The biaxial probe inserted in a previously realized automatic positioning system, operating on a number of specimens of different materials, and with known cracks, proves to be capable of 1) correctly identifying the crack direction and 2) detecting the crack location with an uncertainty contained within the resolution of the automatic positioning system. View full abstract»

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  • Evaluating phase noise power spectrum with variable frequency resolution

    Page(s): 685 - 691
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB) |  | HTML iconHTML  

    Measurement of phase noise affecting sinusoidal carriers is dealt with here. A new method is proposed, mainly intended to overcome the limits of two digital signal-processing solutions, already presented by the authors and devoted, respectively, to far-from-the-carrier and close-to-the-carrier phase noise analysis. Thanks to an original measurement procedure, the method optimizes the frequency resolution in the evaluation of phase noise power spectral density; in particular, the closer to the carrier the analysis, the finer the frequency resolution granted. It is possible to obtain accurate and reliable results in a wide range of frequency offsets with no need for heavy computational burden and expensive hardware resources of the adopted data acquisition system. The results of a number of experiments, conducted on actual sinusoidal carriers through a measurement prototype implementing the method, confirm the efficacy and reliability of the proposal. View full abstract»

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  • Reconstruction algorithms for electromagnetic imaging

    Page(s): 692 - 699
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB) |  | HTML iconHTML  

    Two algorithms for image reconstruction in electromagnetic imaging are proposed. The first approach concerns the application of a hybrid version of the genetic algorithm to tomographic imaging of dielectric configurations. In the second approach, buried inhomogeneities are schematized as multilayer infinite dielectric cylinders with elliptic cross sections. An efficient recursive analytical procedure is used for the forward scattering computation. A cost function is constructed in which the field is expressed in series solution of Mathieu functions. Starting by the input scattered data, the iterative minimization of the functional is performed by a new optimization method called memetic algorithm. View full abstract»

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  • Implementing uncertainty auto-evaluation capabilities on an intelligent FFT analyzer

    Page(s): 700 - 708
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    An fast Fourier transform analyzer with capabilities of auto-configuration, continuous signal analysis, and estimation of spectral component parameters has been provided with the capability of evaluating the uncertainty of the estimated values. The instrument, which has been implemented on a two-DSP hardware, has been characterized through several experimental tests, proving the metrological and operating performances. This paper describes the hardware and the algorithms used for the instrument, and it details the analytical development of the relationships for the uncertainty evaluation and the preliminary compensation of systematic effects. This paper also reports the main experimental results. View full abstract»

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  • Using the parametric time-varying analog filter to average-evoked potential signals

    Page(s): 709 - 715
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (344 KB) |  | HTML iconHTML  

    Processing of the brainstem auditory-evoked potential (BAEP) signal is achieved with a simple averaging over a number of realizations. The proposed filtering method of the BAEP signal is an extremely attractive alternative for long-duration examination with a repeated stimulus. Repetitive stimulation (20-30 times) allows additional averaging to be performed on the signal under extremely high noise conditions. Using averaging in time with a parametric filter (in real time) and then averaging over realizations is a completely new approach to the averaging of the BAEP signal. When we visually compare shapes of responses after a number of realization, we notice that the result of 20 realizations with simultaneous averaging in time with parametric filters is much better than simple, standard averaging with 20 realizations, and also as good as averaging with 1000 realizations. Simple calculations show that the time of examination could be reduced many times. View full abstract»

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  • New digital multimeter for accurate measurement of synchronously sampled AC signals

    Page(s): 716 - 725
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    An approach to the design of a digital multimeter based on the use of dual-slope ADC is described in this paper. Based on this approach, a new technique for algorithm design is developed. The main advantage of this approach is the determination of all electric values in electric utilities by the same algorithm. The algorithm has high accuracy and a regular structure. Measurements of voltage and current are made in successive periods by a stroboscopic technique (synchronous undersampling). The assumed stationarity of the electric utilities is validated by measurements with an experimental setup, consisting of a fast high-precision sigma-delta ADC. The necessary synchronization is reached by software measurements of the frequency of the measured signal. Assuming stationarity of the observed system (electric utilities) in the stated 1-s interval, it is proved that precise digital processing can be achieved without using a sample-and-hold circuit. The suggested measuring system was simulated, realized in a practical setup, and tested. The obtained results completely confirmed the starting postulates. A processing precision of 0.01% was achieved. View full abstract»

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  • Why are nonlinear microwave systems measurements so involved?

    Page(s): 726 - 729
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB) |  | HTML iconHTML  

    Performing nonlinear measurements on microwave devices is a complex task. This paper introduces, step by step, the key concepts that make the difference between linear S-parameter measurements and nonlinear measurements. The main goal here is to make nonlinear measurements more accessible to the practicing microwave engineer. View full abstract»

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  • Performance of simple response method for the establishment and adjustment of calibration intervals

    Page(s): 730 - 735
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    Managing calibration intervals in order to fulfill requirements of quality-oriented organizations is discussed in this paper. In particular, the simple response method is considered. According to this technique, the interval between successive calibrations is adjusted adaptively on the basis of the outcome of the last calibration process. An original analysis is presented about the properties of such calibration interval handling methods. Finally, directions are given on how to tune its parameters optimally, in order to meet desired levels of long-term measurement reliability. View full abstract»

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  • Digital correction techniques for accuracy improvement in measurements of SnO2 sensor impedance

    Page(s): 736 - 743
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB) |  | HTML iconHTML  

    In this paper, the performance improvement of a gas-sensing system by digital correction techniques is discussed. The considered system operates as a vectorial impedance meter and performs impedance measurements of eight sensors arranged in an array in the frequency range 10 Hz-15 MHz. The measurements of the chemical sensors' impedance is an innovative technique that allows highlighting different adsorption mechanisms taking place when the sensors are exposed to gases. Of course, impedance analyzers are commercially available, but they usually make measurements on only one device at time and they are very expensive. The proposed PC-based impedance analyzer is a versatile one and shows good performances for gas-sensing applications. A digital correction technique is used in this work to improve the impedance measurement accuracy of each channel of the gas-sensing system (eight sensors → eight channels), in order to compensate for the conditioning electronics response. The latter is evaluated in a characterization procedure. A linear black box two-port model is used to take into account crosstalk, amplitude, and phase distortions. Two different techniques to evaluate the response of the measurement system are discussed in this paper, and experimental results are presented on both the measure of reference impedances and on the measure of chemical sensors. View full abstract»

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  • Modeling of direction-dependent Processes using Wiener models and neural networks with nonlinear output error structure

    Page(s): 744 - 753
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB) |  | HTML iconHTML  

    The modeling of direction-dependent dynamic processes using Wiener models and recurrent neural network models with nonlinear output error structure is considered. The results obtained are compared for several simulated first-order and second-order processes and using three different types of input signals: a pseudorandom binary signal, an inverse-repeat pseudorandom binary signal and a multisine (sum of harmonics) signal. Experimental results on a real system, namely an electronic nose system, are also presented to illustrate the applicability of the techniques discussed. View full abstract»

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  • Entropy-based optimum test points selection for analog fault dictionary techniques

    Page(s): 754 - 761
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB) |  | HTML iconHTML  

    An efficient method to select an optimum set of test points for dictionary techniques in analog fault diagnosis is proposed. This is done by searching for the minimum of the entropy index based on the available test points. First, the two-dimensional integer-coded dictionary is constructed whose entries are measurements associated with faults and test points. The problem of optimum test points selection is, thus, transformed to the selection of the columns that isolate the rows of the dictionary. Then, the likelihood for a column to be chosen based on the size of its ambiguity set is evaluated using the minimum entropy index of test points. Finally, the test point with the minimum entropy index is selected to construct the optimum set of test points. The proposed entropy-based method to select a local minimum set of test points is polynomial bounded in computational cost. The comparison between the proposed method and other reported test points selection methods is carried out by statistical experiments. The results indicate that the proposed method more efficiently and more accurately finds the locally optimum set of test points and is practical for large scale analog systems. View full abstract»

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  • Pre-estimation for better initial guesses

    Page(s): 762 - 769
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (344 KB) |  | HTML iconHTML  

    Fast, assured convergence of iterative identification methods is important in many on-line applications, including systems that exploit indirect measurements, diagnostics, and model-based control. The transient response of a system can often be mapped directly to an estimate of the system model parameters. This initial estimate, or pre-estimate, can be evaluated in fixed time and may greatly accelerate subsequent iterative system identification procedures. A pre-estimation structure is developed and demonstrated with examples including single-tone frequency estimation and induction motor parameter identification. View full abstract»

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  • Statistical comparison of algorithms

    Page(s): 770 - 776
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB) |  | HTML iconHTML  

    A "reference" algorithm or instrument and its various "distortions" are considered, where the distortions carry some valid information about the reference. The objective is to combine data from the reference and the distortions together in some manner in order to extract information from both the reference, as well as the distortions, and produce improved inference about the true reference algorithm. This is illustrated in terms of m precipitation radars and semiparametric estimation of the reference distribution and the distortion parameters. View full abstract»

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  • Experimental evaluation of a nested microphone array with adaptive noise cancellers

    Page(s): 777 - 786
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB) |  | HTML iconHTML  

    This paper proposes a near-field broadband adaptive beamforming scheme for intelligent computer telephony and teleconferencing applications, namely the nested microphone array with adaptive noise canceller (NMA-ANC). The NMA-ANC scheme incorporates an harmonically nested array with a nonuniformly subbanded multirate filter bank. Each subband array employs several near-field delay-filter-and-sum beamformers and an adaptive noise canceller (ANC). The proposed NMA-ANC is evaluated via a noise rejection experiment and dereverberation experiment performed in an anechoic chamber and a real conference room, respectively. The experiment data are recorded by a multichannel digital recording system developed using commercial off-the-shelf (COTS) equipments. A perceptual analysis/measurement system (PAMS) test is also carried out using a COTS digital speech level analyzer. The results of the experimental evaluation and PAMS test show that the proposed NMA-ANC scheme is able to improve the sound quality by adaptively rejecting multiple interfering signals and attenuating the reverberant noises and avoiding the desired signal cancellation. View full abstract»

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  • Measuring the sensitivity of microwave components to bias variations

    Page(s): 787 - 791
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB) |  | HTML iconHTML  

    This paper presents a method to measure the sensitivity of microwave components to memory effects caused by the dc biasing circuit. This allows us to determine the required (impedance) properties of the dc biasing circuit to reduce slow dynamics under a certain level. The proposed measurement technique is based on the nonlinear vectorial network analyzer, which allows us to measure not only the absolute magnitude but also the absolute phase relations between the waves. Superimposing a multisine excitation signal on the dc bias allows us to measure the slow dynamics caused by the dc biasing circuit as a function of frequency and input power. Furthermore, it is verified whether or not the measured phenomena depend on the type of excitation signal. View full abstract»

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Aims & Scope

Papers are sought that address innovative solutions to the development and use of electrical and electronic instruments and equipment to measure, monitor and/or record physical phenomena for the purpose of advancing measurement science, methods, functionality and applications.

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Editor-in-Chief
Prof. Alessandro Ferrero
Dipartimento di Elettrotecnica
Piazza Leonardo da Vinci 32
Politecnico di Milano
Milano 20133 Italy
alessandro.ferrero@polimi.it
Phone: 39-02-2399-3751
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