Sine wave

About: Sine wave is a research topic. Over the lifetime, 12183 publications have been published within this topic receiving 93013 citations. The topic is also known as: sinusoid.

High torque brushless DC motors and generators

Abstract: This invention relates to geometric, electrical, and electronic techniques improving torque, power, cost, size, weight, reliability, and efficiency of electric generators and motors using the following: Geometric relationships eliminating lateral magnetic short circuits, providing sine wave output waveforms, and allowing axial extendibility; Radial and axial Permanent Magnet concentration; Speed independent rotating transformer inductive coupling; Precise speed independent rotor position sensing using a threshold and comparator circuit to provide Hall Effect low speed & Back-EMF medium to high speed sensing; Bi-directional Buck-Boost PWM converter topology using H-bridge power transistors, parallel reverse diodes and an H-bridge connected inductor.

The generalised Lomb-Scargle periodogram. A new formalism for the floating-mean and Keplerian periodograms

Abstract: The Lomb-Scargle periodogram is a common tool in the frequency analysis of unequally spaced data equivalent to least-squares fitting of sine waves. We give an analytic solution for the generalisation to a full sine wave fit, including an offset and weights ($\chi^{2}$ fitting). Compared to the Lomb-Scargle periodogram, the generalisation is superior as it provides more accurate frequencies, is less susceptible to aliasing, and gives a much better determination of the spectral intensity. Only a few modifications are required for the computation and the computational effort is similar. Our approach brings together several related methods that can be found in the literature, viz. the date-compensated discrete Fourier transform, the floating-mean periodogram, and the "spectral significance" estimator used in the SigSpec program, for which we point out some equivalences. Furthermore, we present an algorithm that implements this generalisation for the evaluation of the Keplerian periodogram that searches for the period of the best-fitting Keplerian orbit to radial velocity data. The systematic and non-random algorithm is capable of detecting eccentric orbits, which is demonstrated by two examples and can be a useful tool in searches for the orbital periods of exoplanets.

Novel AC-DC and DC-DC converters with a diode-capacitor multiplier

Abstract: This paper presents a transformerless ac-dc and or dc-dc converter with a high output voltage multiplicity, which contains only one switch. The converter consists of an inverter and a diode-capacitor multiplier (DCM) and provides a voltage gain equal to double the number of multiplier steps. In the case of ac-dc conversion the proposed converter offers a practically unit power factor and provides a sine wave input current. The analysis of the steady state as well as the transient behavior of the DCM is given and simplified equivalent circuits are proposed. The prototype of the DCM has been built and tested to show the validity of the proposed converter. The theoretical analysis, the computer simulation results, and the experimental testing results are in good agreement.

Pitch for nonsimultaneous successive harmonics in quiet and noise

Abstract: Pitch perception was studied with respect to nonsimultaneous successive harmonics of fundamentals in quiet and noise. Stimuli consisted of three nonoverlapping sine waves each of 40‐msec duration. Pitch perception, examined by discrimination and matching, was found to correspond to spectral frequency in quiet and fundamental frequency in noise. The results suggest a pitch processor that integrates over time (synthetic mode) in noise and analyzes spectral components (analytic mode) in quiet. The findings are discussed with respect to current theories of pitch perception and auditory integrative functions. The findings are thought to be particularly relevant to analytic and synthetic modes of pitch perception.