Topic
Fundamental frequency
About: Fundamental frequency is a research topic. Over the lifetime, 8941 publications have been published within this topic receiving 131583 citations.
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TL;DR: In this article, a wideband open-loop active harmonic load-pull measurement approach is presented, which is based on wideband data-acquisition and wideband signal-injection of the incident and device generated power waves at the frequencies of interest.
Abstract: A new wideband open-loop active harmonic load-pull measurement approach is presented. The proposed method is based on wideband data-acquisition and wideband signal-injection of the incident and device generated power waves at the frequencies of interest. The system provides full, user defined, in-band control of the source and load reflection coefficients presented to the device-under-test at baseband, fundamental and harmonic frequencies. The system capability to completely eliminate electrical delay allows to mimic realistic matching networks using their measured or simulated frequency response. This feature enables active devices to be evaluated for their actual in-circuit behavior, even on wafer. Moreover the proposed setup provides the unique feature of handling realistic wideband communication signals like multicarrier wideband code division multiple access (W-CDMA), making the setup perfectly suited for studying device performance in terms of efficiency, linearity and memory effects.
92 citations
TL;DR: In this article, a method to evaluate harmonic contributions at the point of common coupling is presented, which is based on the harmonic current vector method where reference impedances are introduced, and long-term measurements are proposed for determination of harmonic contributions.
Abstract: A method to evaluate harmonic contributions at the point of common coupling is presented in this paper. The proposed approach is based on the harmonic current vector method where reference impedances are introduced. Resistance defined at fundamental frequency with measurements is used as the customer-side reference impedance. The presented method allows calculation of harmonic contributions without knowing the actual customer impedances. It also enables better evaluation of the customer and utility harmonic contributions in resonance conditions. The method is verified through a simulation study and with extensive field measurements. Long-term measurements are proposed for determination of harmonic contributions.
92 citations
TL;DR: In this paper, a theoretical expression for the work done due to centrifugal effects when a rotating cantilever blade executes small vibrations is derived, based on previously derived expressions for the stationary blade.
Abstract: A theoretical expression is obtained for the work done due to centrifugal effects when a rotating cantilever blade executes small vibrations. The total potential energy and kinetic energy of the system are formulated, use being made of previously derived expressions for the stationary blade.By use of Rayleigh's method an equation for the fundamental frequency of vibration is established and, for the case of a straight blade of uniform and symmetrical cross-section, a solution is deduced based on an approximate shape for the normal elastic curve. The characteristic differential equations of motion for the rotating system are obtained from the energy expressions by use of variational calculus. Coriolis effects, being small, can be neglected in the analyses.
92 citations
TL;DR: The present method is better than previously reported methods in terms of both gross and fine F0 errors and the fundamental frequency is more accurately estimated from reliable harmonic components which are easy to select given the dominance spectra.
Abstract: This paper presents a new method for robust and accurate fundamental frequency (F0) estimation in the presence of background noise and spectral distortion. Degree of dominance and dominance spectrum are defined based on instantaneous frequencies. The degree of dominance allows one to evaluate the magnitude of individual harmonic components of the speech signals relative to background noise while reducing the influence of spectral distortion. The fundamental frequency is more accurately estimated from reliable harmonic components which are easy to select given the dominance spectra. Experiments are performed using white and babble background noise with and without spectral distortion as produced by a SRAEN filter. The results show that the present method is better than previously reported methods in terms of both gross and fine F0 errors.
92 citations
TL;DR: In this article, a method for consistent analysis of a quantum-mechanical system situated in a potential that depends periodically on the time, for example, in the field of a strong classical electromagnetic wave is considered.
Abstract: A method is considered for consistent analysis of a quantum-mechanical system situated in a potential that depends periodically on the time, for example, in the field of a strong classical electromagnetic wave The emission of such a system is considered, and particularly the shift of the fundamental frequency ω' and the appearance of satellites ω' ± hω
91 citations