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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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Journal ArticleDOI
TL;DR: In this paper, an adaptive notch filter (ANF) is proposed for real-time detection and extraction of individual harmonic and interharmonic components in a power signal with potentially time-varying characteristics.
Abstract: A method for real-time detection and extraction of individual harmonic and interharmonic components in a power signal with potentially time-varying characteristics is presented. The proposed method, which is based on the concept of adaptive notch filter (ANF), adaptively decomposes the measured power signal into its constituting components independent of where their frequencies are located. The algorithm provides instantaneous values of the various estimated frequency components in addition to the values of their frequencies, amplitudes, and phase angles. The structure and mathematical formulation of the proposed technique, including guidelines for its parameter tuning, are presented and its performance is studied in a variety of scenarios where the power signal attributes, such as fundamental frequency and amplitude, undergo variations over time. This study confirms the desirable transient and steady-state performances of the proposed method. Compared with its recently proposed counterpart, the proposed method of this paper obviates the need for using a phase-locked loop (PLL), and hence, offers a more simplified structure which makes it more attractive from an implementation point of view.

76 citations

Journal ArticleDOI
TL;DR: The effect of the filter bank on fundamental frequency (F0) discrimination was examined in four Nucleus CI24 cochlear implant subjects for synthetic stylized vowel-like stimuli, and results indicate that F0 discrimination based upon place pitch cues is possible, but just-noticeable differences exceed 1 octave or more depending on the filters used.
Abstract: The effect of the filter bank on fundamental frequency (F0) discrimination was examined in four Nucleus CI24 cochlear implant subjects for synthetic stylized vowel-like stimuli. The four tested filter banks differed in cutoff frequencies, amount of overlap between filters, and shape of the filters. To assess the effects of temporal pitch cues on F0 discrimination, temporal fluctuations were removed above 10 Hz in one condition and above 200 Hz in another. Results indicate that F0 discrimination based upon place pitch cues is possible, but just-noticeable differences exceed 1 octave or more depending on the filter bank used. Increasing the frequency resolution in the F0 range improves the F0 discrimination based upon place pitch cues. The results of F0 discrimination based upon place pitch agree with a model that compares the centroids of the electrical excitation pattern. The addition of temporal fluctuations up to 200 Hz significantly improves F0 discrimination. Just-noticeable differences using both place and temporal pitch cues range from 6% to 60%. Filter banks that do not resolve the higher harmonics provided the best temporal pitch cues, because temporal pitch cues are clearest when the fluctuation on all channels is at F0 and preferably in phase.

76 citations

Journal ArticleDOI
TL;DR: In this article, the authors revisited reversible ac voltammetry from a contemporary viewpoint, stressing aspects that are not confined to small applied voltages, and derived exact formulas that give the heights of the ac voltammograms for both the fundamental and harmonic frequencies when the ac signal Vcos{ωt} is applied across the faradaic element of a reversible working electrode, together with a slowly ramped dc voltage.

76 citations

Journal ArticleDOI
TL;DR: The results provide no evidence that TFS cues are used to code the F0 of unresolved harmonics, and the presence and phase dependence of audible distortion products are measured.
Abstract: At least two modes of pitch perception exist: in one, the fundamental frequency (F0) of harmonic complex tones is estimated using the temporal fine structure (TFS) of individual low-order resolved harmonics; in the other, F0 is derived from the temporal envelope of high-order unresolved harmonics that interact in the auditory periphery. Pitch is typically more accurate in the former than in the latter mode. Another possibility is that pitch can sometimes be coded via the TFS from unresolved harmonics. A recent study supporting this third possibility [Moore et al. (2006a). J. Acoust. Soc. Am. 119, 480–490] based its conclusion on a condition where phase interaction effects (implying unresolved harmonics) accompanied accurate F0 discrimination (implying TFS processing). The present study tests whether these results were influenced by audible distortion products. Experiment 1 replicated the original results, obtained using a low-level background noise. However, experiments 2–4 found no evidence for the use of TFS cues with unresolved harmonics when the background noise level was raised, or the stimulus level was lowered, to render distortion inaudible. Experiment 5 measured the presence and phase dependence of audible distortion products. The results provide no evidence that TFS cues are used to code the F0 of unresolved harmonics.

76 citations

Proceedings ArticleDOI
18 Apr 1994
TL;DR: A high-performance isolator has been developed for a multiaxis isolation system for a large reaction wheel assembly, featuring a tuned, three-parameter configuration that significantly outperforms the more conventional two-parameters design.
Abstract: Presented at the AIAA 35th SDM Conference Hilton Head, South Carolina April 1994 Copyright „ 1994 by Honeywell Inc. A high-performance isolator has been developed for a multiaxis isolation system for a large reaction wheel assembly. Reaction wheel assemblies are used for spacecraft attitude control. The isolator offers significant improvements over prior isolators, providing a low break frequency and featuring a tuned, three-parameter configuration that significantly outperforms the more conventional two-parameter design. A three-parameter system is one that is modeled with spring elements in series and parallel with the damper. Two-parameter systems, as modeled in most vibration texts, have a single spring element in parallel with the damper. The system is tuned by selecting three-parameter values that provide maximum damping at the fundamental frequency and reduced damping at higher frequencies. The mathematical basis for three-parameter isolators with tuning methodology is included. Physical design features of the isolator are described in addition to actual test data that confirms the fundamental performance improvement. The technique for obtaining low suspension frequencies is also discussed.

76 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202344
2022101
2021236
2020335
2019421
2018375