Fundamental frequency

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

Surface acoustic wave harmonic analysis

Abstract: A method for sensing and analyzing data with surface acoustic wave (SAW) devices comprises the steps of: propagating a sampling signal at a fundamental frequency through a SAW device (12) coated for selective adsorption; measuring at least one parameter of at least one higher order harmonic of the fundamental frequency sampling signal; exposing the coated SAW device (12) to enable the selective adsorption; measuring the at least one higher order harmonic of the fundamental frequency sampling signal after the exposing step; comparing the measurements of the at least one parameter of the at least one higher order harmonic before and after the exposing step; and, deriving a result of the selective adsorption based upon the comparing step. The at least one parameter is harmonic power and harmonic frequency. The at least one higher order harmonic is one or more odd harmonics.

29.9 A 4×4 Distributed Multi-Layer Oscillator Network for Harmonic Injection and THz Beamforming with 14dBm EIRP at 416GHz in a Lensless 65nm CMOS IC

Abstract: Integrated high-power THz arrays with beamforming ability can enable new applications in communication, sensing, imaging, and spectroscopy [1]. However, due to the limited power-generation capability of a single source above the device f max [2], efficient spatial power combining from multiple coherent sources becomes necessary to generate mW level of power. To create this 2D array of distributed frequency and phase-locked sources, prior works have shown central LO-signal distribution with local harmonic upconversion [3]. However, this requires high power consumption in the LO distribution. In addition, phase-matching with PVT variations across the sources at the harmonic-radiating THz frequency can be quite challenging. A small ∆θ perturbation at the fundamental frequency translates to N∆θ at the radiated Nth harmonic, thus corrupting the array beam pattern. Another method to synchronize multiple distributed radiating sources (ƛ/2 spaced at Nfo) is through a mutual coupling network with active/passive elements in a coupled oscillator array [4], [5]. However, the locking range in these methods is typically narrow (∆f locking ~ f 0 /20 to f 0 /10) and PVT variations can easily cause desynchronization. In such a network, each cell is a self-sustaining oscillator, and the coupling network tries to establish injection signals to force synchronization between these individual free-running oscillators. In this paper, we used a 2D oscillating network with negative G m (–G m ) cells at each node that do not oscillate individually but only collectively, establishing a robust frequency and phase distribution network across the chip for high THz-power generation. By making this network as the lowest layer, we can now separate the locking mechanism and the power-generation sources. This avoids loading and sub-optimal operation of the power sources. The distributed oscillating network at the lowest layer operates at 69.3GHz, and multi-layer local harmonic generation produces a radiated power of −3dBm and +14dBm EIRP at 416GHz in a 4×4 array.

A Parametric Method for Pitch Estimation of Piano Tones

Abstract: The efficiency of most pitch estimation methods declines when the analyzed frame is shortened and/or when a wide fundamental frequency (Fo) range is targeted. The technique proposed herein jointly uses a periodicity analysis and a spectral matching process to improve the fo estimation performance in such an adverse context: a 60 ms-long data frame together with the whole, 71/4-octaves, piano tessitura. The enhancements are obtained thanks to a parametric approach which, among other things, models the inharmonicity of piano tones. The performance of the algorithm is assessed, is compared to the results obtained from other estimators and is discussed in order to characterize their behavior and typical misestimations.

A magnetic device current injection in a three-phase sinusoidal-current utility interface

Abstract: A magnetic device for current injection in a three-phase, sinusoidal-current utility interface is presented. This class of sinusoidal rectification depends on the injection of a third-harmonic current into the AC side of a three-phase rectifier. The injection network should provide a low and equal impedance in each of the three branches to the modulation current at the third harmonic frequency, and a high impedance to the fundamental frequency voltages. Experimental results from an injection device for a 12.5 kW sinusoidal rectification scheme are presented to support the simulation results obtained by a finite element program. >

Psychoacoustical evaluation of the pitch-synchronous overlap-and-add speech-waveform manipulation technique using single-formant stimuli

Abstract: This article presents two experiments dealing with a psychoacoustical evaluation of the pitch synchronous overlap-and-add (PSOLA) technique. This technique has been developed for modification of duration and fundamental frequency of speech and is based on simple waveform manipulations. Both experiments were aimed at deriving the sensitivity of the auditory system to the basic distortions introduced by PSOLA. In experiment I, manipulation of fundamental frequency was applied to synthetic single-formant stimuli under minimal stimulus uncertainty, level roving, and formant-frequency roving. In experiment II, the influence of the positioning of the so-called “pitch markers” was studied. Depending on the formant and fundamental frequency, experimental data could be described reasonably well by either a spectral intensity-discrimination model or a temporal model based on detecting changes in modulation of the output of a single auditory filter. Generally, the results were in line with psychoacoustical theory on the auditory processing of resolved and unresolved harmonics.