CASPIAN JOURNAL
MANAGEMENT AND HIGH TECHNOLOGIES
Technique of defining low-frequency periodic vibrations in single-bit signals of sigma-delta modulators
 |
Read | Chuvykin Boris V., Dolgova Irina A., Sidorova Irina A. Technique of defining low-frequency periodic vibrations in single-bit signals of sigma-delta modulators // Caspian journal : management and high technologies. — 2014. — №2. — pp. 174-181. |
Chuvykin Boris V. - D.Sc. (Engineering), Penza State University, 40 Krasnaya St., Penza, 440026, Russian Federation, chuvykin_bv@mail.ru
Dolgova Irina A. - Ph.D. (Engineering), Penza State University, 40 Krasnaya St., Penza, 440026, Russian Federation, dolgovair@mail.ru
Sidorova Irina A. - post-graduate student, Penza State University, 40 Krasnaya St., Penza, 440026, Russian Federation, irina-penza@mail.ru
The article is devoted to development of the technique of definition the presence of low-frequency periodic oscillations in single-bit signals of sigma-delta modulators. They are a part of high-precision integrating ADC. This problem is important due to the fact that the special feature of the Sigma-Delta modulator is a complex structure of output single-bit signals that can be both periodic and chaotic oscillations. The structure of these signals depends on the time constants of integrators and the input signal level. The greatest interest are the conditions of occurrence of periodic oscillations, as in this case, synthesize of high-performance digital filters decimators forming high-frequency output ADC code are possible. However, the explicit analytical relationship between the parameters of the sigma-delta modulator and the amplitude of the input signal can not be obtained because the dynamic processes described by nonlinear difference equations of higher order. The technique is based on numerical simulations to determine the presence of low-frequency periodic and quasiperiodic oscillations for selected values of the time constants of integrators of sigma-delta modulators. Recommendations for synthesis of digital notch filters, necessary for the suppression of periodic oscillations in the output bit signals of sigma-delta modulators. An example of analysis Simulink model of the sigma-delta modulator the third order. Simulation results illustrate the presence of the identified linkages between the duration of low-frequency oscillations and numeric of the time constants of integrators, as well as the amplitude of the input signal, expressed in fractional-rational form.
Key words: sigma-delta modulator, sigma-delta ADC, periodic oscillations, chaotic oscillations, a one-bit signal, Simulink-model, the time constants of integrators, сигма-дельта модулятор, сигма-дельта АЦП, периодические колебания, хаотические колебания, однобитный