Topic
Harmonic
About: Harmonic is a research topic. Over the lifetime, 44833 publications have been published within this topic receiving 495922 citations. The topic is also known as: overtone & partial.
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TL;DR: In this article, a constant Q spectral transform that gives a constant pattern in the log frequency domain for sounds with harmonic frequency components has been described and the position of the best approximation to the ideal pattern for the spectra produced by these instruments has been determined.
Abstract: In a recent article [J C Brown, ‘‘Calculation of a Constant Q Spectral Transform,’’ J Acoust Soc Am 89, 425–434 (1991)], the calculation of a constant Q spectral transform that gives a constant pattern in the log frequency domain for sounds with harmonic frequency components has been described This property has been utilized in calculating the cross‐correlation function of spectra of sounds produced by musical instruments with the ideal pattern, which consists of one’s at the positions of harmonic frequency components Therefore, the position of the best approximation to the ‘‘ideal’’ pattern for the spectra produced by these instruments has been determined, and in so doing the fundamental frequency for that sound has been obtained Results are presented for scales produced by the piano, flute, and violin as well as for arpeggios played by a wide variety of instruments
130 citations
TL;DR: In this paper, the response of an infinite two-dimensional periodic structure to point harmonic loading is analyzed and the response amplitude has a relatively smooth spatial distribution; if a caustic is present then the response has a complex spatial pattern and a "dead region" of very low response occurs.
130 citations
TL;DR: In this article, a simple technique of mode-locking is demonstrated using a nonlinear mirror with intensity-dependent reflection coefficient, constituted by a combination of a SHG crystal and a dichroic mirror with high reflectivity for the second harmonic and partial transmission for the fundamental.
130 citations
TL;DR: It is shown that the conical beams are formed as a result of the higher-order nonlinear Bragg diffraction involving two parametric processes in which an ordinary fundamental wave is converted simultaneously into ordinary and extraordinary polarized second harmonics.
Abstract: We report on the observation of second-harmonic conical waves generated in a novel geometry of the transverse excitation of an annular periodically poled nonlinear photonic structure by a fundamental Gaussian beam. We show that the conical beams are formed as a result of the higher-order nonlinear Bragg diffraction involving two parametric processes in which an ordinary fundamental wave is converted simultaneously into ordinary and extraordinary polarized second harmonics.
130 citations
TL;DR: In this paper, a new control strategy of effective fifth and seventh harmonic elimination in the stator output voltage at the point of common coupling for a stand-alone doubly fed induction generator (DFIG) feeding a three-phase diode rectifier was proposed.
Abstract: This paper proposes a new control strategy of effective fifth and seventh harmonic elimination in the stator output voltage at the point of common coupling for a stand-alone doubly fed induction generator (DFIG) feeding a three-phase diode rectifier. This load regularly causes such harmonic distortions, which harmfully affect the performance of other loads connected to the DFIG. In order to allow the DFIG to deliver a pure sinusoidal stator output voltage, these harmonics must be rejected. The proposed elimination method is investigated based on the rotor current controller employing a proportional integral and a resonant controller, which is implemented in the fundamental reference frame. In this frame, both positive seventh and negative fifth voltage harmonic can be eliminated by using only single resonant compensator tuned at six multiples of synchronous frequency in the rotor current controller. The control scheme is developed in the rotor-side converter for the control and operation of the DFIG. Simulations and experimental results with 2.2-kW DFIG feeding a nonlinear load are shown to verify prominent features of the proposed control method.
130 citations