Fundamental frequency

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

Swipe: a sawtooth waveform inspired pitch estimator for speech and music

Abstract: A Sawtooth Waveform Inspired Pitch Estimator (SWIPE) has been developed for processing speech and music. SWIPE is shown to outperform existing algorithms on several publicly available speech/musical-instruments databases and a disordered speech database. SWIPE estimates the pitch as the fundamental frequency of the sawtooth waveform whose spectrum best matches the spectrum of the input signal. A decaying cosine kernel provides an extension to older frequency-based, sieve-type estimation algorithms by providing smooth peaks with decaying amplitudes to correlate with the harmonics of the signal. An improvement on the algorithm is achieved by using only the first and prime harmonics, which significantly reduces subharmonic errors commonly found in other pitch estimation algorithms.

The SIFT algorithm for fundamental frequency estimation

Abstract: In this paper a new method for estimating F 0 , the fundamental frequency of voiced speech versus time, is presented. The algorithm is based upon a simplified version of a general technique for fundamental frequency extraction using digital inverse filtering. It is demonstrated that the simplified inverse filter tracking algorithm (hereafter referred to as the SIFT algorithm) encompasses the desirable properties of both autocorrelation and cepstral pitch analysis techniques. In addition, the SIFT algorithm is composed of only a relatively small number of elementary arithmetic operations. In machine language, SIFT should run in several times real time while with special-purpose hardware it could easily be realized in real time.

Instability of Periodic Wavetrains in Nonlinear Dispersive Systems

Abstract: The defining property of the class of physical systems under consideration herein is that, by striking a balance between nonlinear and frequency-dispersive effects, they can transmit periodic waves of finite amplitude but constant form. For any such system, therefore, in respect of propagation in the x direction relative to a state of rest, the dynamical equations have exact periodic solutions of the form η ( x, t ) = H ( x - ct ), say, where c is a constant phase velocity depending on wave amplitude as well as on frequency or wavelength. This paper is concerned with the proposition that in many cases these uniform wavetrains are unstable to small disturbances of a certain kind, so that in practice they will disintegrate if the attempt is made to send them over great distances. The outstanding example only recently brought to light is that finite gravity waves on deep water are unstable: unmistakable experimental evidence of this property is now available, and it has also been demonstrated analytically. In §2 the essential factors leading to instability are explained in general terms. A disturbance capable of gaining energy from the primary wave motion consists of a pair of wave modes at side-band frequencies and wavenumbers fractionally different from the fundamental frequency and wavenumber. In consequence of a nonlinear effect on these modes counteracting the detuning effect of dispersion on them, they are forced into resonance with second-harmonic components of the primary motion and thereafter their amplitudes grow mutually at a rate that is exponential in time or distance. In §3 a detailed stability analysis is presented for wavetrains on water of arbitrary depth h , and it is shown that they are unstable if the fundamental wavenumber k satisfies kh > 1·363, but are otherwise stable. Finally, in §4, some experimental results regarding the instability of deep-water waves are discussed, and a few prospective applications to other specific systems are reviewed.

A new inverse‐filtering technique for deriving the glottal air flow waveform during voicing

Abstract: A method is described for deriving the volume velocity waveform at the glottis during voiced speech by inverse‐filtering the volume velocity waveform at the mouth. Unlike the previously used technique of inverse‐filtering radiated acoustic pressure, this method provides a signal that is accurate down to zero frequency, not susceptible to low‐frequency noise, and easily calibrated in amplitude by a constant air flow. The primary limitation is the need for a transducer that will measure volume velocity at the mouth with adequate fidelity. In this work, volume velocity was recorded from a specially designed circumferentially vented wire screen pneumotachograph mask which provided a time resolution of 1/2 msec, without serious speech distortion. Inverse‐filtered volume velocity was recorded with two adult male subjects for voicing in the modal register. Typical results are shown which indicate the way in which the glottal waveform varied with changes of fundamental frequency, subglottal pressure, and a dimens...

Joint DOA and multi-pitch estimation based on subspace techniques

Abstract: In this article, we present a novel method for high-resolution joint direction-of-arrivals (DOA) and multi-pitch estimation based on subspaces decomposed from a spatio-temporal data model. The resulting estimator is termed multi-channel harmonic MUSIC (MC-HMUSIC). It is capable of resolving sources under adverse conditions, unlike traditional methods, for example when multiple sources are impinging on the array from approximately the same angle or similar pitches. The effectiveness of the method is demonstrated on a simulated an-echoic array recordings with source signals from real recorded speech and clarinet. Furthermore, statistical evaluation with synthetic signals shows the increased robustness in DOA and fundamental frequency estimation, as compared with to a state-of-the-art reference method.