COMPUTER RESEARCH OF SIGMA-T ADC WITH ANALOG-TO-DIGITAL COMPENSATION
OF ERRORS CAUSED BY EDGE EFFECTS 

Ashanin Vasiliy Nikolaevich, Candidate of engineering sciences, professor, head of sub-department of electrical engineering and transport electrical equipment, Penza State University (40 Krasnaya street, Penza, Russia), eltech@pnzgu.ru
Korotkov Aleksey Aleksandrovich, Design engineer, Research Institute of Electronic and Mechanical Devices (44 Karakozova street, Penza, Russia), E-mail: lexifer@mail.ru

681.586.37

10.21685/2072-3059-2017-4-6

Background. At the present time, converters with sigma−Δ architecture have the greatest linearity of the information conversion function. However, the impossibility of precise binding of measurement results with measurement time due to realization of the necessary operation of digital filtration of a one-bit sequence in the sigma−Δ modulator’s output greatly limits the application if such converters for measuringtasks. The purpose of this work is realize an information conversion algorithm in ADC of sigma-architecture, in which, for the purpose of exception of digital filtration of the modulator’s output signal, the intermediate pulse-width modulated signal is summarized in the adjoining conversion cycles in the time multiply exceeding the period of a private cycle of pulse modulation. Such information converters are called sigma-T ADC. The research is conducted at the level of a computer model using a combined (analog and digital) approach to compensation of errors caused by edge effects. It gives a chance to summarize results of intermediate private cycles of conversion without error accumulation, thus allowing to exclude digital filtration.
Materials and methods. The article considers a combined method of compensation of errors caused by edge effects in integrating sigma-T ADCs. The computer model was created in Simulink environment. The authors have defined mean-square deviation from the linear conversion function with and without compensation of errors caused by edge effects.
Results. The work displays the possibility of realization of sigma-T ADC having high precision of conversion to solve problems of informational and measuring technique. The results of calculation of values of mean-square deviation from the linear function of conversion in integrating ADCs with and without compensation of errors are given.
Conclusions. The developed model of integrating sigma-T ADCs proves a possibility of providing high metrological characteristics of the measuring converter without application of digital filtration of the modulator’s output signal.

integrating sigma-T ADC, error compensation, computer model, edge effect, linearity of conversion function, sigma-Δ modulation, mean-square deviation

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