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F. Adamo, F. Attivissimo, N. Giaquinto
MATLAB TOOLBOXES FOR A/D CONVERTERS CHARACTERIZATION


Mustafa Keskin, Matthew E. Brown, Un-Ku Moonm, Gábor C. Temes
A VOLTAGE-MODE SWITCHED-CAPACITOR BANDPASS ΔΣ MODULATOR

A novel fourth-order voltage-mode switched-capacitor bandpass ΔΣ modulator, using direct-charge-transfer pseudo-N-path resonators, is described. This modulator is insensitive to component mismatches and finite opamp bandwidth, and is also less sensitive to finite opamp gain than previous bandpass ΔΣ data converters. It is therefore suitable for high-speed communications applications.

Tadeusz Zloto, Zygmunt Biernacki, Marek Kurkowski, Pawel Ptak
COMPUTER-AIDED SYSTEM FOR MEASURING TEMPERATURE OF ROTATING ELEMENTS

The paper includes a review of currently used devices for measuring temperature of rotating parts of machines. In the subsequent section it describes a computeraided measuring system developed by the authors. Using the optoelectronic measuring path, the system is employed for measuring temperature of cylinder block of an axial multipiston pump.
Besides, the application of DasyLab software package for the above mentioned measurements is presented.

Marek Kurkowski, Zygmunt Biernacki, Tadeusz Zloto, Pawel Ptak
SIGNAL GENERATION AND ACQUISITION IN THE CORRELATION WTS

The paper deals with problems of signal analysis. Examples of system modelling by means of Dasylab package are discussed.
Measurements, analysis and visual presentation of selected signals were performed by means of measuring card PCL818 and Dasylab package. They are also described in the present paper [7].

Marek Kurkowski, Pawel Ptak, Zygmunt Biernacki, Tadeusz Zloto
ACCURACY OF SIGNAL CONVERSION IN POWER MEASUREMENTS WITH LEM CONVERTERS

Among the phenomena significantly aggravating the quality of electric energy in the grid two are especially important: voltage fluctuations and deformations of voltage and current sinusoids.
The aim of the study described in the present paper was to improve the accuracy of signal converting in power measurements in non-linear receivers. The measurements of voltage and current were performed by means of a PC with measuring a card PCL-818L and with application software DasyLab 6.0 enabling the registration and converting of signals.

Tamás Zoltán Bilau, Tamás Megyeri, Attila Sárhegyi, János Márkus, István Kollár
FOUR PARAMETER FITTING OF SINE WAVE TESTING RESULTS: ITERATION AND CONVERGENCE

Small improvements to the iteration procedure of the IEEE Standard 1241-2001 are suggested, and extension of the standard MATLAB program implementing the sine wave test is discussed. The program is compatible with the LabView program already announced, and in other working modes offers extensions, too.

Jerome J. Blair
CORRECTED RMS ERROR AND EFFECTIVE NUMBER OF BITS FOR SINEWAVE ADC TESTS

A new definition is proposed for the effective number of bits of an ADC. This definition removes the variation in the calculated effective bits when the amplitude and offset of the sinewave test signal is slightly varied. This variation is most pronounced when test signals with amplitudes of a small number of code bin widths are applied to very low noise ADC's. The effectiveness of the proposed definition is compared with that of other proposed definitions over a range of signal amplitudes and noise levels.

Salvatore Nuccio, Ciro Spataro
A SOTWARE TOOL TO ESTIMATE THE MEASUREMENT UNCERTAINTIES IN THE A/D CONVERSION BASED INSTRUMENTS

In the paper we present a numerical method, which permits to evaluate the measurement uncertainties of the A/D conversion based instruments overcoming the possible inapplicability of the pure theoretical approach prescribed in the ISO – "Guide to the Expression of Uncertainty in Measurement".

Y. C. Jenq
FOURIER SPECTRUM OF D/A OUTPUTS WITH NON-UNIFORMLY SAMPLED DATA AND TIME-VARYING CLOCKS

In this paper, we investigate problems of D/A converters with non-uniformly sampled input data, and/or time-varying clock sources. The input digital data (which are stored in the memory to be read out and sent to a D/A converter) were obtained by sampling an analog waveform at non-uniform sampling intervals. (Quantization of data can also be considered as a form of non-uniform sampling.) Recently, there is available a new clocking system with a very fine time resolution and is capable of adjusting the clock period in a sample-to-sample basis. It is, therefore, interesting to consider the following question. "Given that the timing offset of each data sample is known, would it be beneficial to use this offset to adjust the read-out timing of the D/A converter?" To answer this question, we consider the following five different models: f1(t) = Σn x(n T) g(t - n T), f2(t) = Σn x(tn) g(t - n T), f3(t) = Σn x(n T) g(t - tn), f4(t) = Σn x(tn) g(t - tn), and f5(t) = Σn x(tn) gn(t - tn) where x(.) is the input analog signal, g(.) is the basic output pulse waveform of the D/A converter, T is the nominal sampling period and tn is the n-th sampling time instance (for uniform sampling tn = n T). Closed form expressions for the Fourier transform of the output signals for each model are derived. We also discuss some potential practical applications.

F. Attivissimo, N. Giaquinto, M. Savino
CHEBYSHEV POLYNOMIALS AND DITHER TECHNIQUES FOR STATIC CHARACTERISTIC LINEARIZATION IN A/D CONVERTERS

The paper illustrates a new procedure, simple and very fast, to measure and correct the linearity error in A/D converters. The method is based on the Chebyshev polynomial synthesis of the static characteristic via frequency-domain analysis, and is especially effective for dithered converters.

Page 737 of 936 Results 7361 - 7370 of 9356