Meaningful information on the internal state of a battery can be derived by measuring its impedan... more Meaningful information on the internal state of a battery can be derived by measuring its impedance. Accordingly, battery management systems based on electrochemical impedance spectroscopy are now recognized as a feasible solutions for online battery control and diagnostic. Since the impedance of a battery is always changing along with its state of charge and aging effects, it is important to have a stable impedance reference in order to calibrate and test a battery management system. In this work we propose a programmable impedance emulator that in principle could be used for the calibration of any battery management system based on electrochemical impedance spectroscopy. A digital finite-impulse-response filter is implemented, whose frequency response is programmed so as to reproduce exactly the impedance of a real battery in the frequency domain. The whole design process of the filter is presented in detail. An analytical expression for the impedance of real battery in the freque...
Instrumentation and Measurement, IEEE …, Jan 1, 1994
The effect of adding dither to a given signal before its quantization is investigated. To this ai... more The effect of adding dither to a given signal before its quantization is investigated. To this aim the relationship between the statistical description of the dither and the mean value of the quantization error and of the quantizer output is derived. The presented results allow the determination of the resolution limits that can be achieved by low-pass filtering a set of quantized samples of a slowly varying dithered signal. Discrete, uniform, sinusoidal, and Gaussian dithering are analyzed, thus providing a quantitative basis for choosing the most appropriate dither signal for a given application.
Instrumentation and Measurement, IEEE …, Jan 1, 1998
In the paper, the authors consider the performance of histogram-based analog to digital converter... more In the paper, the authors consider the performance of histogram-based analog to digital converter (ADC) testing under the assumption of input-equivalent wideband noise, which models either noise sources inside the device or unwanted disturbances corrupting the stimulus signal employed for carrying out the test. Theoretical relationships are presented which allow the design of the test parameters needed to meet a given test accuracy. Moreover, it is shown, that the histogram test is effective in providing information on the deterministic behavior of the tested device and that it can be made insensitive to the effects of inputequivalent noise. Finally, the obtained results are employed to determine the test performance in estimating the device effective number of bits, and simulations results are provided which validate the theoretical derivations.
In this paper, the frequency-domain dynamic test of analog-to-digital converters (ADCs) is consid... more In this paper, the frequency-domain dynamic test of analog-to-digital converters (ADCs) is considered under the assumption of noncoherent sinewave sampling. A procedure is described which is based on the windowed discrete Fourier transform (WDFT), optimized for the achievement of high estimation accuracy. To this aim, the class of windows belonging to the set of discrete prolate spheroidal sequences is adopted for the reduction of the effects of spectral leakage. Practical suggestions are given for a straightforward applicability of derived results and for an efficient estimation of ADC spectral parameters. Finally, experimental results are presented in order to validate the proposed testing approach.
In this paper, the problem of identifying variations in the nature of atomic clock noise is addre... more In this paper, the problem of identifying variations in the nature of atomic clock noise is addressed. Two methods are proposed. One method is based on a generalized likelihood ratio test (GLRT), and the other is based on the dynamic Allan variance (DAVAR), which is a representation of the instantaneous clock stability that is able to point out possible nonstationary behaviors. Both methods efficiently track variations in the experimental clock data and, thus, appear as suitable tools for the detection of atomic clock anomalies.
This paper describes in detail a Java-based, clientserver architecture specifically designed to a... more This paper describes in detail a Java-based, clientserver architecture specifically designed to allow a flexible management of remote instruments. The main attributes of the proposed solution are portability and extensibility. The former feature is assured by the employment of the TCP/IP protocol suite and by the Java language properties. The latter is due to the high level of abstraction of the system implementation. This approach addresses a wide range of possible applications with high code reusability. In fact, the proposed architecture permits to drive many kinds of different devices and can be easily upgraded simply by adding a limited amount of code on the server computer whenever a new instrument is connected to the system. Index Terms-Client-server architecture, distributed measurement system (DMS), Java native interface, remote calibration.
The Remote Didactic Laboratory Laboratorio Didattico Remoto-LA.DI.RE. "G. Savastano" is the e-lea... more The Remote Didactic Laboratory Laboratorio Didattico Remoto-LA.DI.RE. "G. Savastano" is the e-learning measurement laboratory supported by the Italian Ministry of Education and University. It involves about 20 Italian universities and provides students of electric and electronic measurement courses with access to remote measurement laboratories delivering different didactic activities related to measurement experiments. In order to demonstrate the versatility for didactic use, the Manuscript
Instrumentation and Measurement, IEEE …, Jan 1, 2000
In this paper, the authors discuss the use of deterministic and stochastic dither sequences in an... more In this paper, the authors discuss the use of deterministic and stochastic dither sequences in analog-to-digital conversion including data postprocessing. Properties of both types of dither signals are highlighted, and a performance comparison is carried out by considering residual bias and mean square error. It is concluded that superior performance can be attained by deterministic dither in terms of system resolution and accuracy, at the expense of worse spectral characteristics. Experimental results are provided to support simulations and theoretical analysis. . His research interests cover the application of digital signal-processing techniques to measurement science and the issues related to their practical implementation.
The consequences of dithering on nonlinear quantizers are analyzed. A model of the nonlinear quan... more The consequences of dithering on nonlinear quantizers are analyzed. A model of the nonlinear quantizer is considered, and a model of the same quantizer with dither is proposed. By means of this approach, relationships are given for the total quantization error in the case of discrete binary, uniform, and Gaussian dither signals.
… IMTC 2000. Proceedings of the 17th …, Jan 1, 2000
In this paper, the accuracy of ADC sinewave histogram testing is analyzed under the assumption of... more In this paper, the accuracy of ADC sinewave histogram testing is analyzed under the assumption of quasicoherent sampling. A bound is derived on the inaccuracy in setting the ratio between sinewave and sampling frequencies, which allows the design of the test for prescribed levels of estimator variance. Detailed proofs and simulation results are presented.
This paper proposes a frequency-based least squares algorithm applied to the estimation of multif... more This paper proposes a frequency-based least squares algorithm applied to the estimation of multifrequency signal parameters. It is based on the processing of the joint information carried by nearby frequency components of Fourier-transformed data. Theoretical and simulated analysis are carried out on the algorithm accuracy, while its performance is compared to the corresponding Cramer-Rao (CR) lower bound.
In many wireless applications, it is necessary to demodulate and digitize frequency or phase modu... more In many wireless applications, it is necessary to demodulate and digitize frequency or phase modulated signals. Most commonly, this is done using separate frequency discrimination and analog-to-digital (A/D) conversion. In low-cost IC technologies, such as CMOS, precise analog frequency discrimination is not practical, so the A/D conversion is usually performed in quadrature or at a nonzero intermediate frequency (IF) with digital frequency discrimination. While practical, the approach tends to require complicated A/D converters, and accuracy is usually limited by the quality of the A/D conversion. This paper presents an alternative structure, referred to as a delta-sigma frequency-to-digital converter (16FDC), that simultaneously performs frequency demodulation and digitization.
Instrumentation and Measurement, IEEE …, Jan 1, 1997
This paper addresses the problem of designing quantizing systems employing dither. These are comp... more This paper addresses the problem of designing quantizing systems employing dither. These are composed of a dither generator, a quantizer, a subtracting block and a low-pass digital filter. Quantitative criteria for choosing the parameters that influence the resolution and accuracy of the quantizing system are given, and the system performance is determined under worst, best, and average conditions for discrete binary, uniform, and Gaussian dither signals. The results presented also can be applied when the signal plus input-referred noise are quantized.
The evaluation of spectral parameters characterizing analog-to-digital converters (ADC) is addres... more The evaluation of spectral parameters characterizing analog-to-digital converters (ADC) is addressed by applying a single or dual tone generator to the device input and by properly processing its output data stream. The coherent sampling condition, highly recommended by the IEEE standards 1057 and 1241 which list the most effective ADC testing procedures, is usually difficult to achieve, and sometimes even unfeasible.
This paper presents an analysis of the statistical efficiency of the sinewave histogram test used... more This paper presents an analysis of the statistical efficiency of the sinewave histogram test used for estimating the unknown transition levels of an analog-to-digital converter. Accordingly, at first, a closed-form determination of the Cramér-Rao bound is derived under the assumption of a noiseless stimulus signal. Both unbiased and biased versions of the bound are described in order to account for the eventual bias introduced by commonly employed estimators. Then, additive Gaussian noise is assumed, and comments are made about its effects on the maximum achievable accuracy.
In this paper, a general mathematical framework which permits the determination of simple express... more In this paper, a general mathematical framework which permits the determination of simple expressions for the statistical parameters that characterize the behaviour of uniform quantizers subject to noisy input signals is proposed. Mean values and variances of quantizer output and ...
This paper deals with the effectiveness of the sinewave histogram test (SHT) for testing analog-t... more This paper deals with the effectiveness of the sinewave histogram test (SHT) for testing analog-to-digital converters. The implementation is discussed, with respect to the adopted procedures and to the choice of relevant parameters. Some of the published approximations currently limiting the characterization of the test performance are removed. The statistical efficiency of the SHT is evaluated by comparing the associated estimator variance with the corresponding Cramér-Rao lower bound, theoretically derived assuming sinewaves corrupted by Gaussian noise. Finally, both simulation and experimental results are presented to validate the proposed approach Index Terms-Cramér-Rao lower bound (CRLB), sinewave histogram test (SHT).
… , 2004. IMTC 04. Proceedings of the …, Jan 1, 2004
In this paper, the Cramér-Rao Lower Bound (CRLB) for the parametric estimation of quantized sinew... more In this paper, the Cramér-Rao Lower Bound (CRLB) for the parametric estimation of quantized sinewaves is analyzed, including the effect of analog-to-digital-converter (ADC) noise. An accurate model based on the statistical properties of quantized data is presented, which takes into account both the effects of the finite ADC resolution and of the quantizer overloading phenomena at a low computational cost. Then, the model is validated by comparing the obtained results with the CRLB based on the ADC uniform noise model.
Meaningful information on the internal state of a battery can be derived by measuring its impedan... more Meaningful information on the internal state of a battery can be derived by measuring its impedance. Accordingly, battery management systems based on electrochemical impedance spectroscopy are now recognized as a feasible solutions for online battery control and diagnostic. Since the impedance of a battery is always changing along with its state of charge and aging effects, it is important to have a stable impedance reference in order to calibrate and test a battery management system. In this work we propose a programmable impedance emulator that in principle could be used for the calibration of any battery management system based on electrochemical impedance spectroscopy. A digital finite-impulse-response filter is implemented, whose frequency response is programmed so as to reproduce exactly the impedance of a real battery in the frequency domain. The whole design process of the filter is presented in detail. An analytical expression for the impedance of real battery in the freque...
Instrumentation and Measurement, IEEE …, Jan 1, 1994
The effect of adding dither to a given signal before its quantization is investigated. To this ai... more The effect of adding dither to a given signal before its quantization is investigated. To this aim the relationship between the statistical description of the dither and the mean value of the quantization error and of the quantizer output is derived. The presented results allow the determination of the resolution limits that can be achieved by low-pass filtering a set of quantized samples of a slowly varying dithered signal. Discrete, uniform, sinusoidal, and Gaussian dithering are analyzed, thus providing a quantitative basis for choosing the most appropriate dither signal for a given application.
Instrumentation and Measurement, IEEE …, Jan 1, 1998
In the paper, the authors consider the performance of histogram-based analog to digital converter... more In the paper, the authors consider the performance of histogram-based analog to digital converter (ADC) testing under the assumption of input-equivalent wideband noise, which models either noise sources inside the device or unwanted disturbances corrupting the stimulus signal employed for carrying out the test. Theoretical relationships are presented which allow the design of the test parameters needed to meet a given test accuracy. Moreover, it is shown, that the histogram test is effective in providing information on the deterministic behavior of the tested device and that it can be made insensitive to the effects of inputequivalent noise. Finally, the obtained results are employed to determine the test performance in estimating the device effective number of bits, and simulations results are provided which validate the theoretical derivations.
In this paper, the frequency-domain dynamic test of analog-to-digital converters (ADCs) is consid... more In this paper, the frequency-domain dynamic test of analog-to-digital converters (ADCs) is considered under the assumption of noncoherent sinewave sampling. A procedure is described which is based on the windowed discrete Fourier transform (WDFT), optimized for the achievement of high estimation accuracy. To this aim, the class of windows belonging to the set of discrete prolate spheroidal sequences is adopted for the reduction of the effects of spectral leakage. Practical suggestions are given for a straightforward applicability of derived results and for an efficient estimation of ADC spectral parameters. Finally, experimental results are presented in order to validate the proposed testing approach.
In this paper, the problem of identifying variations in the nature of atomic clock noise is addre... more In this paper, the problem of identifying variations in the nature of atomic clock noise is addressed. Two methods are proposed. One method is based on a generalized likelihood ratio test (GLRT), and the other is based on the dynamic Allan variance (DAVAR), which is a representation of the instantaneous clock stability that is able to point out possible nonstationary behaviors. Both methods efficiently track variations in the experimental clock data and, thus, appear as suitable tools for the detection of atomic clock anomalies.
This paper describes in detail a Java-based, clientserver architecture specifically designed to a... more This paper describes in detail a Java-based, clientserver architecture specifically designed to allow a flexible management of remote instruments. The main attributes of the proposed solution are portability and extensibility. The former feature is assured by the employment of the TCP/IP protocol suite and by the Java language properties. The latter is due to the high level of abstraction of the system implementation. This approach addresses a wide range of possible applications with high code reusability. In fact, the proposed architecture permits to drive many kinds of different devices and can be easily upgraded simply by adding a limited amount of code on the server computer whenever a new instrument is connected to the system. Index Terms-Client-server architecture, distributed measurement system (DMS), Java native interface, remote calibration.
The Remote Didactic Laboratory Laboratorio Didattico Remoto-LA.DI.RE. "G. Savastano" is the e-lea... more The Remote Didactic Laboratory Laboratorio Didattico Remoto-LA.DI.RE. "G. Savastano" is the e-learning measurement laboratory supported by the Italian Ministry of Education and University. It involves about 20 Italian universities and provides students of electric and electronic measurement courses with access to remote measurement laboratories delivering different didactic activities related to measurement experiments. In order to demonstrate the versatility for didactic use, the Manuscript
Instrumentation and Measurement, IEEE …, Jan 1, 2000
In this paper, the authors discuss the use of deterministic and stochastic dither sequences in an... more In this paper, the authors discuss the use of deterministic and stochastic dither sequences in analog-to-digital conversion including data postprocessing. Properties of both types of dither signals are highlighted, and a performance comparison is carried out by considering residual bias and mean square error. It is concluded that superior performance can be attained by deterministic dither in terms of system resolution and accuracy, at the expense of worse spectral characteristics. Experimental results are provided to support simulations and theoretical analysis. . His research interests cover the application of digital signal-processing techniques to measurement science and the issues related to their practical implementation.
The consequences of dithering on nonlinear quantizers are analyzed. A model of the nonlinear quan... more The consequences of dithering on nonlinear quantizers are analyzed. A model of the nonlinear quantizer is considered, and a model of the same quantizer with dither is proposed. By means of this approach, relationships are given for the total quantization error in the case of discrete binary, uniform, and Gaussian dither signals.
… IMTC 2000. Proceedings of the 17th …, Jan 1, 2000
In this paper, the accuracy of ADC sinewave histogram testing is analyzed under the assumption of... more In this paper, the accuracy of ADC sinewave histogram testing is analyzed under the assumption of quasicoherent sampling. A bound is derived on the inaccuracy in setting the ratio between sinewave and sampling frequencies, which allows the design of the test for prescribed levels of estimator variance. Detailed proofs and simulation results are presented.
This paper proposes a frequency-based least squares algorithm applied to the estimation of multif... more This paper proposes a frequency-based least squares algorithm applied to the estimation of multifrequency signal parameters. It is based on the processing of the joint information carried by nearby frequency components of Fourier-transformed data. Theoretical and simulated analysis are carried out on the algorithm accuracy, while its performance is compared to the corresponding Cramer-Rao (CR) lower bound.
In many wireless applications, it is necessary to demodulate and digitize frequency or phase modu... more In many wireless applications, it is necessary to demodulate and digitize frequency or phase modulated signals. Most commonly, this is done using separate frequency discrimination and analog-to-digital (A/D) conversion. In low-cost IC technologies, such as CMOS, precise analog frequency discrimination is not practical, so the A/D conversion is usually performed in quadrature or at a nonzero intermediate frequency (IF) with digital frequency discrimination. While practical, the approach tends to require complicated A/D converters, and accuracy is usually limited by the quality of the A/D conversion. This paper presents an alternative structure, referred to as a delta-sigma frequency-to-digital converter (16FDC), that simultaneously performs frequency demodulation and digitization.
Instrumentation and Measurement, IEEE …, Jan 1, 1997
This paper addresses the problem of designing quantizing systems employing dither. These are comp... more This paper addresses the problem of designing quantizing systems employing dither. These are composed of a dither generator, a quantizer, a subtracting block and a low-pass digital filter. Quantitative criteria for choosing the parameters that influence the resolution and accuracy of the quantizing system are given, and the system performance is determined under worst, best, and average conditions for discrete binary, uniform, and Gaussian dither signals. The results presented also can be applied when the signal plus input-referred noise are quantized.
The evaluation of spectral parameters characterizing analog-to-digital converters (ADC) is addres... more The evaluation of spectral parameters characterizing analog-to-digital converters (ADC) is addressed by applying a single or dual tone generator to the device input and by properly processing its output data stream. The coherent sampling condition, highly recommended by the IEEE standards 1057 and 1241 which list the most effective ADC testing procedures, is usually difficult to achieve, and sometimes even unfeasible.
This paper presents an analysis of the statistical efficiency of the sinewave histogram test used... more This paper presents an analysis of the statistical efficiency of the sinewave histogram test used for estimating the unknown transition levels of an analog-to-digital converter. Accordingly, at first, a closed-form determination of the Cramér-Rao bound is derived under the assumption of a noiseless stimulus signal. Both unbiased and biased versions of the bound are described in order to account for the eventual bias introduced by commonly employed estimators. Then, additive Gaussian noise is assumed, and comments are made about its effects on the maximum achievable accuracy.
In this paper, a general mathematical framework which permits the determination of simple express... more In this paper, a general mathematical framework which permits the determination of simple expressions for the statistical parameters that characterize the behaviour of uniform quantizers subject to noisy input signals is proposed. Mean values and variances of quantizer output and ...
This paper deals with the effectiveness of the sinewave histogram test (SHT) for testing analog-t... more This paper deals with the effectiveness of the sinewave histogram test (SHT) for testing analog-to-digital converters. The implementation is discussed, with respect to the adopted procedures and to the choice of relevant parameters. Some of the published approximations currently limiting the characterization of the test performance are removed. The statistical efficiency of the SHT is evaluated by comparing the associated estimator variance with the corresponding Cramér-Rao lower bound, theoretically derived assuming sinewaves corrupted by Gaussian noise. Finally, both simulation and experimental results are presented to validate the proposed approach Index Terms-Cramér-Rao lower bound (CRLB), sinewave histogram test (SHT).
… , 2004. IMTC 04. Proceedings of the …, Jan 1, 2004
In this paper, the Cramér-Rao Lower Bound (CRLB) for the parametric estimation of quantized sinew... more In this paper, the Cramér-Rao Lower Bound (CRLB) for the parametric estimation of quantized sinewaves is analyzed, including the effect of analog-to-digital-converter (ADC) noise. An accurate model based on the statistical properties of quantized data is presented, which takes into account both the effects of the finite ADC resolution and of the quantizer overloading phenomena at a low computational cost. Then, the model is validated by comparing the obtained results with the CRLB based on the ADC uniform noise model.
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