Fundamental frequency

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

Pitch of Complex Tones: Rate-Place and Interspike Interval Representations in the Auditory Nerve

Abstract: Harmonic complex tones elicit a pitch sensation at their fundamental frequency (F0), even when their spectrum contains no energy at F0, a phenomenon known as "pitch of the missing fundamental." The strength of this pitch percept depends upon the degree to which individual harmonics are spaced sufficiently apart to be "resolved" by the mechanical frequency analysis in the cochlea. We investigated the resolvability of harmonics of missing-fundamental complex tones in the auditory nerve (AN) of anesthetized cats at low and moderate stimulus levels and compared the effectiveness of two representations of pitch over a much wider range of F0s (110-3,520 Hz) than in previous studies. We found that individual harmonics are increasingly well resolved in rate responses of AN fibers as the characteristic frequency (CF) increases. We obtained rate-based estimates of pitch dependent upon harmonic resolvability by matching harmonic templates to profiles of average discharge rate against CF. These estimates were most accurate for F0s above 400-500 Hz, where harmonics were sufficiently resolved. We also derived pitch estimates from all-order interspike-interval distributions, pooled over our entire sample of fibers. Such interval-based pitch estimates, which are dependent on phase-locking to the harmonics, were accurate for F0s below 1,300 Hz, consistent with the upper limit of the pitch of the missing fundamental in humans. The two pitch representations are complementary with respect to the F0 range over which they are effective; however, neither is entirely satisfactory in accounting for human psychophysical data.

Modal Vocal Fundamental Frequency of Young Adults

Abstract: Recordings of 100 male and 100 female young adults who were judged to have normal speech, voice, and hearing were analyzed for vocal fundamental frequency. A technique of determining modal fundamental frequency by systematic screening of the recorded samples through variable filters was employed. The mean of the vocal fundamental frequencies of males was found to be 116.65 hertz and the mean of the vocal fundamental frequencies of females was 217.00 Hz.

The Stability of the Horizontal-to-Vertical Spectral Ratio of Triggered Noise and Earthquake Recordings

Abstract: The aim of this work is to analyze the stability of the amplification function obtained by the horizontal-to-vertical spectral ratio (HVSR) for a sedimentary site with a simple geomorphological situation. We have estimated the stability of the HVSR analyzing two years of data, composed of 674 triggered noise records (man-made seismic waves strong enough to reach the threshold set for earthquake detection) and 132 earthquakes (local, regional, and teleseismic events). The resonance peaks obtained with the two different data sets converge on an average both in frequency and amplitude. We examined and rejected the possible presence of periodicity of the fundamental frequency in the time sequences and its relevant amplification obtained by the HVSR of both triggered noises and earthquakes. Then, we performed a correlation analysis between these sequences and other parameters. In particular they have been correlated with signal amplitude, rainfall, and magnitude (for earthquakes only). A weak, negative correlation has been estimated between the rainfall and fundamental frequency and between the fundamental peak9s amplification and magnitude. Finally, we validated the HVSR transfer function with a 1D model using a V s profile obtained with the noise analysis of surface wave technique (Louie, 2001).

Experimental study of self-sustained oscillations in a confined jet.

Abstract: We present an experimental study of a planar jet confined in a rectangular cavity. In certain geometrical configurations and for sufficiently large Reynolds numbers, this system exhibits self-sustained oscillations characterized by a well-defined wavelength and frequency of the jet. We describe flow regimes observed by varying the Reynolds number and the cavity length. The self-sustained oscillation regime is studied in detail: we extract the fundamental frequency and determine the selection criterion for the wavelength using a method of visualization, which has the advantage of being non intrusive. We show the existence of a band of allowed wavelengths and establish the upper and lower limits for the wavelength selection criterion. We discuss the validity of the visualization method for the measurement of the wavelength and frequency using a simple analytical model of the streaklines. \textcopyright{} 1996 The American Physical Society.

Frequency Analysis and Pitch Perception

Abstract: This chapter is concerned with two main areas: frequency analysis and pitch perception. Frequency analysis refers to the action of the ear in resolving (to a limited extent) the sinusoidal components in a complex sound; this ability is also known as frequency selectivity and frequency resolution. It plays a role in many aspects of auditory perception but is most often demonstrated and measured by studying masking. Studies of pitch perception are mainly concerned with the relationships between the physical properties of sounds and the perceived pitches of those sounds and with the underlying mechanisms that explain these relationships. One important aspect of pitch perception is frequency discrimination, which refers to the ability to detect changes in frequency over time and which is (at least partly) a separate ability from frequency selectivity.