Showing papers on "Fundamental frequency published in 1978"
01 Jan 1978
TL;DR: A survey and research on the phonetics of tone perception and its implications for models of tonal perception and linguistic theory in general can be found in this paper, where the authors present a survey and a discussion of the implications for tone perception.
Abstract: Publisher Summary This chapter presents a survey and research on the phonetics of tone perception and discusses its implications for models of tone perception and linguistic theory in general. It is generally assumed that the principal phonetic features of tone are found in the domain of pitch. The term tone (linguistic) refers to a particular way in which pitch is utilized in language; the term pitch (nonlinguistic, perceptual), on the other hand, refers to how a hearer places a sound on a scale going from low to high without considering the physical properties of the sound. Its primary acoustic correlate is fundamental frequency. The term fundamental frequency (acoustic) refers to the frequency of repetition of a sound wave of which, when analyzed into its component frequencies, the fundamental is the highest common factor of the component frequencies. The function of the ear is to receive the acoustic signal, convert it to electro-chemical energy, and transmit the signal via nerve impulses to the brain.
117 citations
TL;DR: In this article, the second-order sensitivity of natural frequencies is analyzed for the design of a midplane symmetric aluminum beam of constant depth supporting three nonstructural masses, and the web thickness and chord member areas were determined so as to achieve minimum structural mass while maintaining the fundamental frequency at or above 30 Hz.
Abstract: The paper is concerned with structural optimization problems in which the constraints consist of limits imposed on the natural frequencies of the structure. Improvements in the quality of approximations for the frequency constraints are sought by considering second-order Taylor series expansions. Analysis of the second-order sensitivity of natural frequencies is carried out. As an example, the design of a midplane symmetric aluminum beam of constant depth supporting three nonstructural masses is considered. Web thickness and chord member areas were determined so as to achieve minimum structural mass while maintaining the fundamental frequency at or above 30 Hz.
74 citations
TL;DR: In this article, a real-time harmonic pitch detection algorithm was developed on the Lincoln Digital Voice Terminal (LDVT), which was designed to be fast and to perform well when the input speech is degraded (i.e., telephone quality) or corrupted with acoustically coupled noise.
Abstract: A real-time harmonic pitch detection algorithm has been developed on the Lincoln Digital Voice Terminal (LDVT). The algorithm was designed to be fast and to perform well when the input speech is degraded (i.e., telephone quality) or corrupted with acoustically coupled noise. The algorithm determines the fundamental frequency from the spacing between harmonics in a selected portion of the spectrum. The algorithm was incorporated into a real-time linear prediction vocoder and compared favorably in informal listening tests with the Gold-Rabiner time-domain detector under a variety of adverse conditions.
64 citations
TL;DR: The appearance of square gratings with some of their Fourier components missing has been investigated for both threshold and suprathreshold contrasts in discrete-time Fourier analysis.
Abstract: 1. The appearance of square gratings with some of their Fourier components missing has been investigated for both threshold and suprathreshold contrasts.
2. If high frequency components are removed from a square grating there is only a very small effect on the detection threshold, or suprathreshold appearance, unless the components are visible by themselves.
3. If the fundamental frequency is removed from a square-wave grating which has a spatial frequency lower than 1 cycle per degree (c/d) the contrast sensitivity is not altered. This is a generalisation of the Craik-Cornsweet illusion. If the contrast is raised above the detection threshold the grating is indistinguishable from a square grating, unless the contrast is high enough to see the fundamental when it is presented alone.
4. If the fundamental is removed from a square grating which has a spatial frequency higher than 1 c/d the contrast threshold and the appearance at all contrasts are changed. At threshold it appears as a sinusoidal grating of three times the fundamental frequency. The threshold is dictated solely by the amplitude of the third harmonic. If the contrast is further raised, so that the fifth harmonic also reaches threshold, the periodictiy of the fundamental is seen.
5. Therefore, gratings of many different luminance profiles (including the Craik-Cornsweet profile) all produce the perception of a square grating simply because those missing components which would be required in each case to produce a perfect square are by themselves undetectable. The visual system responds as though hardwired to detect square gratings and edges by means of quasi-Fourier analysis.
6. These results are analagous to the missing fundamental, or residue, effect in hearing.
53 citations
40 citations
TL;DR: Fundamental frequency ranges of six normal infants and children from 33 to 169 weeks were determined by narrow-band spectrographic analysis, well outside the values reported in previous studies of noncry utterances.
Abstract: Fundamental frequency ranges of six normal infants and children from 33 to 169 weeks were determined by narrow‐band spectrographic analysis. Fundamental frequency values ranged from 30 to 2500 Hz, well outside the values reported in previous studies of noncry utterances. The use of fry, modal, and high registers is also discussed.
37 citations
Patent•
25 Sep 1978
TL;DR: In this paper, a system for generating output pulses in successive periods of time, each including sub-intervals during which the output pulses may be varied in accordance with a pre-determined scheme.
Abstract: This system generates output pulses in successive periods of time, each including sub-intervals during which the output pulses may be varied in accordance with a pre-determined scheme The time periods and sub-intervals within the periods are defined by means of signals derived from a fundamental clock frequency generation circuit and first and second parallel sets of frequency division circuits connected to the fundamental frequency generation circuit The first set of frequency division circuits is used together with a sub-interval timing circuit to define the sub-intervals of time included in each period A system control means is connected to the frequency generation and division circuits, the timing circuits, a means for entering information into the system defining the periods and sub-intervals and the characteristics of output waveforms to be produced in each sub-interval, and to a variable electrical signal generation means which produce the output waveforms in accordance with the information entered into the system Since the time periods, sub-intervals and output waveforms are all variable in accordance either with a pre-determined scheme, or on a real time basis depending on response of a subject under test, this system may be used to generate complex strings of waveforms especially suitable for measuring responses of biological samples to stimulation by electrical signals in pharmacological, physiological and other biomedical applications
36 citations
28 citations
TL;DR: The psychophysical bias of vowel is also found to depend upon the power spectrum and negatively correlated to the magnitude of the F0 production discrepancies of the average vowel sounds.
Abstract: This study investigates two types of psychophysical pitch bias, one related to vowel acoustical characteristics and the other to sequential order. Based on the analysis of the variation of the subjective equality of pitch in subjects’ responses, a multivariate interaction model is used to explain the experimental results and also to demonstrate the existence of the two types of psychophysical pitch bias. The first pitch bias related to a vowel acoustical characteristic is due to the vowel quality difference as a pitch difference at equal fundamental frequency. By using / / as a common reference, this bias for three test vowels /e, i, u/ is found to be lower than / / by values of 0.54 1.25, and 2.80 Hz, respectively. The other pitch bias related to acoustical characteristic is due to the vowel intensity difference. With intensity difference ranges from 0 to 30 dB, the pitch shift (bias) does not exceed 0.2 Hz at a test F0 of 100 Hz. Apparently, an intensity difference produces insignificant pitch shift in ...
24 citations
TL;DR: In this article, a method of obtaining approximate fundamental frequencies of slightly non-circular plates with free circular cutouts was developed, and an approximate expression for the radius of each bounding curve was written as a truncated Fourier series.
19 citations
TL;DR: A shift of the stimulus with contrast fixation (proximally, roughly equivalent to changing fixation) was usually sufficient to produce an apparent change of waveform, and F + 3F phase-specific effects were found only for apparent changes in the waveform shape.
TL;DR: The derivation of the equations of motion for a system consisting of two identical parallel cantilevers joined by a rigid connector at their free ends is given in this article. Butler et al. show that the longitudinal and flexural deformations of the system are coupled through the boundary conditions but not through the differential equations.
Patent•
06 Jun 1978
TL;DR: In this article, a low contrast measurement apparatus for measuring video signal modulation under low contrast scene conditions is presented. But the measurement apparatus is not suitable for high contrast scenes, and it cannot be used to measure very low contrast ratios.
Abstract: A low contrast measurement apparatus for electronically measuring video signal modulation under low contrast scene conditions. The measurement apparatus utilizes a low contrast periodic optical bar chart in conjunction with a filter-integrator processor to measure very low contrast ratios. The filter-integrator processor contains a filter which is tuned to the corresponding fundamental frequency of the bar chart, thereby reducing the noise bandwidth and consequently improving the signal-to-noise ratio. The filtered signal is integrated over one whole picture frame which results in an improved signal to noise ratio. The integrated output of the filtered video signal constitutes a linearly increasing ramp with a period equal to the frame time and whose height is proportional to the amplitude of the periodic signal.
TL;DR: In this paper, the dynamical behavior of a three-layer cantilever beam damped by a viscoelastic core is studied and two selected boundary conditions are compared, one of them requiring the omission of the hypothesis used by several authors that the ratio of the longitudinal displacements in the elastic parts of the beam is constant.
TL;DR: In this article, the title problem is solved using polynomial approximations and a weighted residuals approach, and a very simple, yet accurate, approximate fundamental frequency equation can be generated.
Patent•
19 May 1978
TL;DR: In this paper, it was shown that the difference between the search frequency signal rates and the common beat oscillator signal rate can change at a rate that is far in excess of any change, in hertz, directly produced in each search fundamental frequency signal by varied object proximateness.
Abstract: A directional concealed object locator, say metal detector, employing a beat frequency oscillator and at least two search oscillators. The search oscillators each include a loop antenna which in part serves to determine the search frequency signal rate of each oscillator and functionally serves to produce an electromagnetic field of relatively large proportions from each loop antenna which is portably so orientable as to have the extended electromagnetic field lines, which emanate from each loop antenna, separately coupled to a buried, or otherwise obscured metal object and thereby produce changes in the search signal rate as the proximity therebetween is varied. The common beat oscillator produces a signal so related to each search frequency signal as to be conjointed in a heterodyne detector and therefrom produce at least two audio frequency notes the resultant periodicities of which are proportional to the difference between each of the search frequency signal rates and the common beat oscillator signal rate. Further improvement is provided in that each resultant audio frequency difference rate is aggrandized so as to change at a rate, in hertz, which is far in excess of any change, in hertz, directly produced in each search fundamental frequency signal by varied object proximateness. The effect is to cause an apparent increased sensitivity, which is shown in one form so as to be variable, in the operation of the metal detector, while at the same time providing proximal resolution by way of a left-hand, or else right-hand, indication of the hidden object transversal path.
TL;DR: In this article, the axial vibration of a cantilever beam is investigated numerically and the mass distribution that minimizes the total mass for a given fundamental frequency constraint is determined using both the sequential gradient-restoration algorithm (SGRA) and an ad hoc modification of the modified quasilinearization algorithm (MQA).
Abstract: : The problem of the axial vibration of a cantilever beam is investigated numerically. The mass distribution that minimizes the total mass for a given fundamental frequency constraint is determined using both the sequential gradient-restoration algorithm (SGRA) and an ad hoc modification of the modified quasilinearization algorithm (MQA).
TL;DR: In this paper, the optimal design of uniform non-homogeneous beams undergoing transverse vibrations is investigated, and the optimal longitudinal modulus distribution is sought to produce the maximum value of fundamental frequency for a beam of given mass and geometry.
TL;DR: In this article, a waveform is generated by making a pulse train with frequency n times the fumdamental frequency, leading the pulse train to a counter activating cyclically and sequentially n different outputs.
Abstract: The device of the invention extracts a fundamental frequency from signals coming from a played musical instrument. From this is synthesized a waveform with the same fundamental frequency which can be given an arbitrary form, so that an audical impression of e.g. a violin, a trumpet or a guitar can be given to sound produced by the waveform. The waveform is produced by making a pulse train with frequency n times the fumdamental frequency, leading the pulse train to a counter activating cyclically and sequentially n different outputs. The outputs are summed with different and adjustable weights, and the waveform is determined by adjusting the n weights. The number n can be any number. An embodiment is shown with n=16.
TL;DR: In this article, a technique originally used for studying contraction properties of skeletal muscles was applied to study of the musculature controlling fundamental frequency (F0), and continuous records of electromyographic activity from laryngeal muscles and of voice fundamental frequency were obtained from a subject producing steady, sustained phonation at low F0.
Abstract: A technique originally used for studying contraction properties of skeletal muscles was applied to study of the musculature controlling fundamental frequency (F0). Continuous records of electromyographic activity from laryngeal muscles and of voice fundamental frequency were obtained from a subject producing steady, sustained phonation at low F0. The fundamental frequency record exhibits small perturbations around a nominally constant value. An average‐response computation of fundamental frequency triggered by single firings in the cricothyroid muscle exhibits a systematic pulse in the interval immediately following the firings. The pulse apparently represents the average effect on F0 of a single twitch in the muscle. This result implicates variability of motor input as a contributing factor in F0 perturbation. The same technique can be used to investigate the effect of other muscles on F0. Using this technique, muscles whose activity is grossly intercorrelated during ongoing F0 control can be uncorrelate...
TL;DR: The fundamental frequencies of the voices during oral reading of 12 stuttering and 12 nonstuttering 7-to-12-year-old males matched according to age, height, weight, and race were studied.
Patent•
24 Apr 1978
TL;DR: A polyphonic tone synthesizer in which two or more distinct voices are sounded by operation of a single key can be found in this article, where the master data list for each voice is calculated repetitively during the time the key is operated by multiplying coefficients with a set of sinusoid values and continuously scaling the resultant product by an envelope scale factor which changes with time to correspond to the desired envelope waveform.
Abstract: A polyphonic tone synthesizer in which two or more distinct voices are sounded by operation of a single key. While the voices have the same fundamental frequency, they are made audibly distinct by differing in harmonic content and differing in the shape of the envelope of the voice signal. The two or more voices are synthesized by alternately calculating master data lists of the amplitude values representative of points on the waveforms of the two voices, adding the two master data lists and converting the resulting values to an analog waveform by feeding the data to a digital-to-analog converter at a rate determined by the fundamental frequency of the note. The master data list for each voice is calculated repetitively during the time the key is operated by multiplying a set of coefficients with a set of sinusoid values and continuously scaling the resultant product by an envelope scale factor which changes with time to correspond to the desired envelope waveform. A single ADSR (attack/decay) generator may be time shared with each voice calculation to provide a differently changing envelope scale factor for each voice.
TL;DR: In this article, a method of determining the fundamental frequency or pitch period of a voice signal from a difference signal, formed with the aid of predictors, between the original voice signal and the voice signal estimated by the predictor is presented.
Abstract: A method of determining the fundamental frequency or pitch period of a voice signal from a difference signal, formed with the aid of predictors, between the original voice signal and the voice signal estimated by the predictor. Only the significant characteristics of the difference signal are then auto-correlated and the maxima of the correlation coefficients determine the fundamental frequency or pitch period.
TL;DR: In this article, the fundamental frequency of transverse vibration of rectangular plates with edges elastically restrained against rotation and subjected to uniformly distributed in-plane normal and shear stresses is determined.
Patent•
03 Oct 1978
TL;DR: In this article, the subwaveguide is coupled via the coupling holes on E or H plane of the major waveguide so the recommended frequency band is the n th harmonic to the fundamental frequency band.
Abstract: PURPOSE:To pick up only the n th harmonic component with separation, by coupling the subwaveguide via the coupling holes on E or H plane of the major waveguide so the recommended frequency band is the n th harmonic to the fundamental frequency band.
TL;DR: In this article, a general derivation of expressions for lower bounds to fundamental frequencies and buckling loads is given for the class of structures governed by linear elastic theory in the prebuckling state.
TL;DR: In this paper, the use of polynomial approximations and a variational approach allows for a very simple determination of the fundamental frequency of vibration in two cases of practical interest and results are obtained for several values of width to length ratios.
Abstract: It is shown that use of polynomial approximations and a variational approach allows for a very simple determination of the fundamental frequency of vibration in two cases of practical interest and results are obtained for several values of width to length ratios.
01 Oct 1978
TL;DR: In this article, surface wave resonators have been used extensively in narrow band applications and new SAW resonator structures have been described, which have the same impedance characteristics over a large band as bulk wave Resonators operating at fundamental frequency.
Abstract: Acoustic surface wave resonators have been used extensively in narrow band applications. In this paper new SAW resonator structures are described, which have the same impedance characteristics over a large band as bulk wave resonators operating at fundamental frequency. Theoretical and experimental results obtained for those SAW resonators show that they can readily be incorporated in large bandwidth ladder or lattice filters for VHF frequencies.