Example[ edit ] Let G be the free group with two generators, a and b, and let E be the subgroup consisting of all reduced words that are products of evenly many generators or their inverses. A factorization of any reduced word in E into these generators and their inverses may be constructed simply by taking consecutive pairs of symbols in the reduced word.
Peterchev, Student Member, Seth R. Power Electron" Abstract—This paper discusses the presence of steady-state limit cycles in digitally controlled pulse-width modulation PWM converters, and suggests conditions on the control law and the quantization resolution for their elimination. It then introduces single-phase and multi-phase controlled digita It then introduces single-phase and multi-phase controlled digital dither as a means of increasing the effective resolution of digital PWM DPWM modules, allowing for the use of low resolution DPWM units in high regulation accuracy applications.
Bounds on the number of bits of dither that can be used in a particular converter are derived. Finally, experimental results confirming the theoretical analysis are presented.
Index Terms—Analog-digital conversion, digital control, dither, finite wordlength effects, power conversion, pulse-width modulation, Show Context Citation Context Dither Generation Scheme Fig.
A novel application and generalization of sigma--delta 61 modulation has emerged in three-phase power-electronic converters. A conventional modulator with scalar signals and binary quantizer is generalized to a modulator with vector signals and a hexagonal quantizer.
Indeed, power-electronic switching states may be thought of as determining the quantizer outputs.
The output spectrum is a key performance measure for both communications and power electronics. This paper analytically derives the output spectrum of the hexagonal modulator with a constant input using ergodic theory and Fourier series on the hexagon.
The switching rate of the modulator is important for power-electronic design and formulas for the average switching rate are derived for constant and slowly varying sinusoidal inputs.
Index TermsErgodic, power electronics, quantization, sigma--delta 61 modulation, spectral analysis. Design techniques for sigma-delta modulators from communications are applied and adapted to improve the spectral characteristics of high frequency power electronic applications.
We review one dimensional sigma-delta modulators and then generalize to the hexagonal sigma-delta modulators that are appropriate to three-phase converters.
A range of interpolative modulator designs from communications can then be generalized and applied to power electronic circuits. White noise spectral analysis of sigma-delta modulators is generalized and applied to analyze the designs so that the noise can be shaped to design requirements.
Simulation results for an inverter show significant improvements in spectral performance. Show Context Citation Context The SNR versus inpIn noting the links that can be made between BLOOMBERG and VOLPE and the teaching and learning discussion that is emerging regarding qualitative research methods, BREUER and SCHREIER's () introductory typology of "paradigmatic" and "pragmatic" approaches to qualitative research is .
Thesis: "Bandpass Sigma-Delta Analog-To-Digital Conversion" Adviser: Martin Snelgrove. I also worked very closely with Richard Schreier (who at the time was a Ph.D. student in our group) and Paul Title: Ph.D., Senior Director, Analog . View Stephen Jantzi’s profile on LinkedIn, the world's largest professional community.
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See the complete profile on LinkedIn and discover Stephen’s connections and jobs at similar companies. Richard Schreier is 79 years old and was born on 10/1/ Currently, he lives in Leesburg, FL; and previously lived in Delray Beach, FL and Lakeland, leslutinsduphoenix.commes Richard goes by various nicknames including dick paul schreier and richard l schreier.
His ethnicity is Caucasian, and religious views are listed as Christian. AN ABSTRACT OF THE THESIS OF Bo Wang for the degree of Doctor of Philosophy in Electrical & Computer Engineering presented on November 6, Title: High-Accuracy Circuits for On-ChipCapacitor Ratio Testing and Sensor Readout.
Bernd Schafferer, Richard Adams; “A 3V CMOS mW 14b GS/s DAC for multi-carrier applications”, IEEE International Solid-State Circuits Conference, vol. XVII, pp. - , February More recent, more resolution; Has techniques to make tail node jumps independent of signal.