Fundamental frequency

About: Fundamental frequency is a research topic. Over the lifetime, 8941 publications have been published within this topic receiving 131583 citations.

Switched mode power supply for single-phase boost commercial AC users in the range of 1 kw to 10 kw

Abstract: A DC to AC power converter is disclosed which is connectable to a DC source, and including a first and second pair of switches which converts the DC source directly to AC by alternately switching between each of the first pair of switches at high frequency modulation, and between second pairs of switches alternately switching at each of the half cycles of the low frequency fundamental output voltage, for producing a positive pulse train and a negative pulse train A transformer boosts the source voltage to the desired high voltage of the output of the converter circuit A filter is connectable to an AC load and having a plurality of damping modes for extracting fundamental frequency from the output of the transformer, and having a control responsive to a signal for switching between damping modes A sine wave oscillator generates a sine wave at the fundamental frequency Feedback circuits maintain the AC output at the fundamental frequency

Multiple fundamental frequency estimation using Gaussian smoothness

Abstract: The goal of a polyphonic music transcription system is to extract a score from an audio signal. A multiple fundamental frequency estimator is the main piece of these systems, whereas tempo detection and key estimation complement them to correctly extract the score. In this work, in order to detect the fundamental frequencies that are present in a signal, a set of candidates are selected from the spectrum, and all their possible combinations are generated. The best combination is chosen in a frame by frame analysis by applying a set of rules, taking into account the harmonic amplitudes and the spectral smoothness measure described in this work. The system was evaluated and compared to other works, yielding competitive results and performance.

Second harmonic generation in metamaterials based on homogeneous centrosymmetric nanowires

Abstract: We present a comprehensive theoretical study of the second harmonic generation (SHG) in metamaterials consisting of arbitrary distributions of cylindrical nanowires made of centrosymmetric materials. The electromagnetic field at both the fundamental frequency (FF) and second harmonic (SH), as well as the total cross section, the absorption cross section, and the scattering cross section, are calculated by means of a numerical algorithm based on the multiple scattering method. Our algorithm fully describes the nonlinear optical response of the metamaterial by incorporating the contributions of both the surface and bulk nonlinear polarizations and can be applied to both s- and p-polarized incident waves. We use this numerical method to investigate the SHG in a series of particular cases of practical interest, namely, a single metallic cylinder, chains of metallic cylinders, and periodic and random distributions of such cylinders. In particular, we study the relation between the local field enhancement, via the excitation of surface plasmon-polariton modes, and the amount of energy absorbed or scattered in the far-field, at the FF and the SH.