Showing papers on "Fundamental frequency published in 1976"

Study of variations in the male and female glottal wave.

Abstract: A reflectionless metal tube which can act as a pseudoinfinite termination of the vocal tract was used to collect glottal volume‐velocity waveforms produced by 10 male and female adult subjects From each subject, glottal volume‐velocity samples were collected of normal, loud, and soft voice; falsetto and creaky voice; monosyllables with rising and falling intonation; and three‐syllable utterances containing primary lexical stress on one of the three syllables Analysis of the data indicates a wide variation of the glottal waveform shape, its rms intensity and fundamental frequency, phase spectrum, and intensity spectrum It is observed that as the fundamental frequency changes over time, the glottal source varies in one of two different ways In one type of change, the harmonic relations in the glottal spectrum become steeper as fundamental frequency rises In a different type of glottal‐wave change, relations between harmonics tend to remain the same despite a change in the fundamental frequency; the source spectrum in this case is simply shifted along the frequency and amplitude axes as a function of fundamental frequency To account for these variations in the glottal source, at least three factors must be known: the sex of the speaker, the voice register in which he phonates, and the linguistic context in which the phonation occurs

Vibrotactile frequency for encoding a speech parameter

Abstract: Frequency of vibration has not been widely used as a parameter for encoding speech‐derived information on the skin. Where it has been used, the frequencies employed have not necessarily been compatible with the capabilities of the tactile channel, and no determination was made of the information transmitted by the frequency variable, as differentiated from other parameters used simultaneously, such as duration, amplitude, and location. However, several investigators have shown that difference limens for vibration frequency may be small enough to make stimulus frequency useful in encoding a speech‐derived parameter such as the fundamental frequency of voiced speech. In the studies reported here, measurements have been made of the frequency discrimination ability of the volar forearm, using both sinusoidal and pulse waveforms. Stimulus configurations included the constant‐frequency vibrations used by other laboratories as well as frequency‐modulated (warbled) stimulus patterns. The frequency of a warbled stimulus was designed to have temporal variations analogous to those found in speech. The results suggest that it may be profitable to display the fundamental frequency of voiced speech on the skin as vibratory frequency, though it might be desirable to recode fundamental frequency into a frequency range more closely matched to the skin’s capability.

Speech coding hearing aid system utilizing formant frequency transformation

Abstract: A hearing aid system and method includes apparatus for receiving a spoken speech signal, apparatus coupled to the receiving apparatus for determining at successive intervals in the speech signal the frequency and amplitude of the largest formants, apparatus for determining at successive intervals the fundamental frequency of the speech signal, and apparatus for determining at successive intervals whether or not the speed signal is voiced or unvoiced. Each successively determined formant frequency is divided by a fixed value, greater than 1, and added thereto is another fixed value, to obtain what are called transposed formant frequencies. The fundamental frequency is also divided by a fixed value, greater than 1, to obtain a transposed fundamental frequency. At the successive intervals, sine waves having frequencies corresponding to the transposed formant frequencies and the transposed fundamental frequency are generated, and these sine waves are combined to obtain an output signal which is applied to a transducer for producing an auditory signal. The amplitudes of the sine waves are functions of the amplitudes of corresponding formants. If it is determined that the speech signal is unvoiced, then no sine wave corresponding to the transposed fundamental frequency is produced and the other sine waves are noise modulated. The auditory signal produced by the transducer in effect constitutes a coded signal occupying a frequency range lower than the frequency range of normal speech and yet which is in the residual-hearing range of many hearing-impaired persons.

Efficient second‐harmonic generation in three‐dimensional LiNbO3 optical waveguide

Abstract: Highly efficient second‐harmonic generation using a titanium in‐diffused LiNbO3 three‐dimensional optical waveguide was performed with the cw Nd : YAG laser at 1.064‐μm wavelength. The phase‐matching condition to convert the TE00 fundamental frequency to the TM00 or TM20 second harmonic was demonstrated by adjusting the crystal temperature. The conversion efficiency is 1.5×10−4 at 2‐mW fundamental input power under the phase‐matching condition. By using a low‐loss LiNbO3 optical waveguide, equipped with highly reflective cavity mirrors on the input and output surfaces, parametric oscillation is expected.

Simple frequency expression for the in‐plane vibration of thick circular rings

Abstract: A simple frequency equation is derived for the in‐plane vibration of thick rings, taking account of the effects of transverse shear and rotatory inertia. The remarkable accuracy of the expression is demonstrated by comparison with experimental data.Subject Classification: [43]40.26.

Subharmonic pitches of a pure tone at low S/N ratio

Abstract: 2AFC scores were obtained on 50 untrained subjects who had to respond to a 3% increment or decrement of the fundamental frequency of two successive signals. The first signal in each trial was a reference, containing six harmonics of 200 Hz. Main variables were the number of harmonics of the second signal in a trial (either 3, 2, or 1) and the presence or absence of continuous background noise. Low scores were observed in the absence of the noise (typically 65% for the 3‐ and 2‐component signals, and virtually 50% for the 1‐component signals), whereas in the presence of the noise much higher scores were observed (typically 90% and 80%, respectively). The results indicate that background noise has great impact on the perceptibility of a ’’low pitch’’ related to the fundamental frequency, even more so than the number of components presented (within the range of three, two, or one components): at a low S/N ratio, even a single harmonic may give rise to the perception of a subharmonic low pitch. Subsequent exp...

Fundamental frequency and perceived vowel duration

Abstract: What is the relationship between variations in fundamental frequency and perceived duration? At the last meeting of the Society, Prof. Lehiste presented some data dealing with this question. Basically, she found that when listeners are asked to judge the duration of pairs of vowels of equal duration they typically judge the first member of the pair as longer than the second. However, when the second member of the pair contained some variation in FO, listeners perceived it as longer than the first stimulus. In this paper we present the results of two experiments that bear on the general questions raised by Prof. Lehiste's findings. Subjects were presented with all possible pairs of synthetic vowels which varied in duration (160, 200, 240 msec) and fundamental frequency (falling: 200–90 Hz; level: 145 Hz; or rising: 90–200 Hz). They were asked to judge which vowel was longer. The results showed that, in general, vowels containing either a rise or a fall in fundamental frequency were perceived as longer than the corresponding vowels with level fundamentals. These findings were true regardless of the order of presentation of the pair of vowels. The results will be discussed in terms of the interaction between segmental and suprasegmental cues in speech perception. [Research supported by NINCDS Grants NS‐12179‐01 and NS‐07040‐01.]

Method and apparatus for microwave frequency counting

Abstract: A microwave input signal whose frequency is to be determined is mixed in a mixer with a local oscillator (LO) signal and the resultant difference signal is applied to a low pass filter. The frequency of the LO signal is controlled by a digital processor that samples the output of the low pass filter. Initially the LO signal is at zero. Thereafter, the frequency of the LO signal is sequentially stepped through the fundamental and, then, the harmonics of a principal oscillator signal having a fundamental frequency F R . When the difference frequency falls within the direct counting capability of a digital counter, the digital processor opens a main gate for a short period of time, and a first difference frequency (F 1 ) count is made and stored. The frequency of the LO signal is then offset by a known amount, and a second difference frequency (F 2 ) count is made and stored -- if this F 2 count is within the direct counting capability of the digital counter. Alternatively, if this F 2 count lies beyond the direct counting capability of the digital counter, the frequency of the LO signal is stepped to the next F R offset harmonic and, then, an alternate F 2 count is made and stored. The relationship between F 1 and F 2 determines whether or not the LO signal frequency, when the counts were made, was above or below the frequency of the input signal. Subsequent to the F 1 and F 2 counts being made and stored, the main gate is again opened, this time for a precise period of time related to the requisite resolution required and the digital counter makes and stores a third difference frequency (F 3 ) count. F 3 is algebraically summed with the LO signal frequency produced when F 3 was determined, to obtain a displayable count equal to the frequency of the input signal. A jitter generator is provided to randomly frequency modulate the LO signal to preclude phase lock between the LO signal and the input signal, when the F 1 and F 2 counts are being made and stored during a counting sequence.

Microwave diode coaxial circuit oscillator improvement

Abstract: An improvement in a prior art microwave diode coaxial oscillator circuit comprising an unloaded fundamental frequency cavity for prevention of energy loss in the matching termination at the resonant frequency of the circuit and a second harmonic resonant cavity for controlling second harmonic loading of the diode and for reducing noise in the output signal.

Electronic musical instrument having memories containing waveshapes of different type

Abstract: A plurality of waveshape memories are provided for storing the sampled values of one cycle sinusoidal wave as the fundamental frequency, two cycle sinusoidal wave as the second harmonic, . . . and m cycle sinusoidal wave as the m-th harmonic and, in addition thereto, of harmonic-abundant complex waves such as a triangular wave, a sawtooth wave and a rectangular wave. These waveshape memories are read at the same reading rate. The read out sinusoidal waves and triangular, sawtooth and rectangular waves are controlled in their relative levels in accordance with the tone-color of an intended musical tone wave shape. The sinusoidal waves and the triangular, sawtooth and rectangular waves are thereafter synthesized to produce a desired tone-color wave shape. Since the triangular, sawtooth and rectangular waves contain abundant harmonic components, many kinds of musical tones containing abundant harmonic components can be produced despite a limited number of waveform memories.

Frequency tunable microwave apparatus having a variable impedance hybrid idler circuit

Abstract: A frequency tunable microwave apparatus including a semiconductor TRAPATT diode generating a microwave signal at its fundamental, second and third harmonic frequencies. Energy is extracted at the second harmonic frequency and a certain impedance loading is provided at the fundamental frequency and third harmonic by a variable impedance hybrid idler circuit. The hybrid idler circuit comprises a distributed transmission line serially connected to a lumped variable capacitor. Variations in the capacitance of the variable capacitor tune the fundamental frequency without substantially varying the impedance loading conditions of the diode allowing energy to be extracted at the second harmonic frequency throughout the tunable frequency range.

System for measuring vibration frequency of vibrating object

Abstract: A system for measuring the vibration frequency of a vibrating object useful for the adjustment of the vibration frequency of a piano string or like vibrating objects. In this system, the vibration of the vibrating object is converted to an electric signal, based on which signal is sought the difference between the vibration frequencies of any two adjacent harmonics of the vibrating object, i.e. the fundamental vibration frequency of the vibrating object is sought. The electric signal is led to a counter via a voltage-controlled variable band-pass filter. The middle frequency of the pass-band of this filter is controlled by a sweeper and varies continuously. For each agreement of this middle frequency of the pass-band with any one of the harmonics, the output of the filter presents a peak. The frequency corresponding to each peak is detected by a counter. The fundamental frequency is calculated from the difference between the frequencies corresponding to any adjacent peaks of the outputs of the filter. In another aspect of the system, the electric signal of vibration discussed above is inputted respectively, to a pair of band-pass filters whose respective middle frequencies are selected so as to agree with the frequencies of any adjacent two harmonics, and the outputs are multiplied by a multiplier. From the multiplied signal is derived, through a low-pass filter, a lower frequency component which now has the aimed fundamental vibration frequency.

Low frequency triangular waveform generator

Abstract: A low frequency triangular waveform generator mixes two high frequency squarewaves having a constant frequency difference to produce a triangular waveform with a fundamental frequency equal to the difference in the fundamental frequencies of the mixed squarewaves. This generator can be adapted to produce squarewaves, sine waves, sawtooth waves, and asymmetrical triangular waves without the use of digital accumulators or ROMs.

Engine diagnosis from frequency components in exhaust

Abstract: An engine diagnostic apparatus includes a transducer for translating an exhaust pressure waveform emitted by an engine to a corresponding complex electrical signal having a prominent fundamental frequency component which represents the cylinder firing frequency and varies in direct proportion with engine speed, and having a subharmonic frequency component at a frequency which is a submultiple of the fundamental frequency. The subharmonic frequency component and the fundamental frequency component are separated from the complex electrical signal and from each other. A comparator compares the amplitude of the subharmonic frequency component with the amplitude of the fundamental frequency component to provide a measure of the unevenness of power strokes from individual cylinders of the engine.

Electronic sensing and measuring apparatus for signals in audio frequency range

Abstract: Electronic sensing and measuring equipment for accurately measuring the pitch of musical sounds and which includes an audio tuner responsive to the fundamental frequency of a continuing signal while rejecting all other harmonically related components of said signal to produce a digital signal representing the fundamental pitch of said musical sound, and a counter for counting and totalizing said digital signal defining the same in terms of its frequency and for visually displaying said defined signal.

Dynamic Properties of a Moving Thread Line

Abstract: A mathematical model representing the transverse vibration of axially moving elastic strings is presented considering tension and mass variation A suggested numerical scheme was successfully used to solve the nonlinear partial differential equations of motion For axially nonmoving strings, the effect of initial amplitudes, and consequently the tension variation on the fundamental frequency is obtained Also, the effect of the initial tension and the mass of the string per unit length on the fundamental frequency and their corresponding mathematical relations are presented For axially moving strings, the effect of the axial velocity on the fundamental frequency as well as the tension distribution along the thread is given Also the behavior of the string at velocities equal and greater than the wave speed is shown

Fundamental Frequency Estimation

Abstract: The fundamental frequency (F0) is a basic parameter in acoustical studies of speech. It is also a necessary parameter for low bit rate speech coding systems. It is generally considered to be one of the acoustical correlates to the perceived intonation pattern of speech. If the fundamental frequency of a speaker is constant, the speech would be perceived as being machine-like or monotone. If the speaker is excited, the fundamental frequency generally increases. It is the acoustical correlate to the rate at which the vocal folds open and close (or vibrate). If the folds are vibrating rapidly, a high fundamental frequency will be measured. In the linear speech production model, the fundamental frequency is the rate at which glottal volume velocity pulses are applied to the vocal tract, i.e., the driving function to the model is periodic with a period of 1/F0.

Stroboscopic tuning device for musical instruments

Abstract: A stroboscopic tuning device for a stringed musical instrument that is mounted on the musical instrument adjacent to the strings to be tuned A solid state circuit employs a frequency generator, such as a piezoelectric crystal oscillator or a tuning fork oscillator, to operate the stroboscopic light source at a preselected frequency In the use of the device, a string is plucked, and when the vibratory motion of the plucked string is either the fundamental frequency or the harmonic frequency of the preselected operating frequency of the stroboscopic light source, the string will appear to an operator to be in a nonvibrating condition At that time, the string is tuned or adjusted to the desired tone

A comparative study of noise properties of Si IMPATT diodes operating at 80 GHz

Abstract: The oscillator-noise properties of three kinds of Si IMPATT diodes operating at 80 GHz are measured. A DDR type of diode is superior in FM noise measure to the other two SDR types, one of which operates in the fundamental frequency mode and the other in the second harmonic frequency mode.

Technology Transfer in the Vibration Analysis of Linearly Tapered Cantilever Beams

Abstract: Curves are presented for determining the fundamental frequency and several higher harmonics for cantilever beams linearly tapered in the vertical or the horizontal plane or tapered in both planes simultaneously (double taper); both the single-tapered and the double-tapered beams are treated with free end, end mass, and end support.

Ultrasonic recording of the fundamental frequency of a voice during normal speech.

Abstract: A continuous wave of ultrasound through larynx is used to determine the fundamental frequency of the vocal folds during normal speech. The variation of the ultrasound intensity transmitted between two matched transducers through the vocal fold level is recorded. The apparatus used for these recordings is described. Different transducer positions are investigated, and further, the transducer geometry is discussed.