摘要:

A basic method of speech synthesis is discussed in which segments of recorded utterances are joined together to produce continuous speech. The segments are characterized as (A) containing parts of two phones with their mutual influence in the middle of the segment, and (B) beginning and ending at the phonetically most stable position of each phone. All segments containing the same articulatory sequence have been defined as adyad. The method of synthesis described involves not only the articulatory phones, but also the intonation, stress, and durational aspects of speech. Various techniques of obtaining the segments for speech synthesis are discussed. The method is limited to a specific dialect, and practically it is limited to a single speaker. A large number of segments is required to synthesize any arbitrarily selected utterance within these restrictions of dialect and speaker.

ISSN:0001-4966    

DOI:10.1121/1.1930009

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

The corner‐reflector antenna for electromagnetic radiation has been studied theoretically by J. B. Kraus [Proc. Inst. Radio Engrs.28, 513 (1940)] and experimentally by E. F. Harris [Proc. Inst. Radio Engrs.41, 645 (1953)], as well as others. However, little use has been made of analogous reflector for beam pattern formation with sonar transducers. The simple image theory of the corner reflector is reviewed in the light of applications to the acoustic case. Theoretical results for reflected impedance, forward gain, and radiation pattern are in good agreement with experimental results. In order to obtain a narrow‐beam, high intensity underwater‐sound projector, a corner reflector has been constructed, tested, and used. The transducer element consists of a line of BaT:O cylinders located in the bisectional plane of a 90° corner reflector. Impedance, gain and pattern have been investigated as a function of the distance in wavelengths of the transducer element from the line of intersection of the two reflecting surfaces. To date, only the 90° reflector has been examined. As a means for acoustic‐pattern formation, the corner reflector is of simpler construction than the cylindrical parabola and offers the advantage that the beam pattern can be readily changed by altering the reflector position and angle.

ISSN:0001-4966    

DOI:10.1121/1.1930013

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

Directional hydrophones on naval vessels are often limited in listening performance by acoustic interference arising from discrete sources such as propellers, pumps, or discharges. While a directional hydrophone may achieve some discrimination against such sources, the effectiveness of this discrimination is limited by the minor‐lobe response in the direction of the source of interference. In an ideally homogeneous, unbounded medium, the minor‐lobe characteristics of a directional hydrophone would be determined completely by the characteristics of the hydrophone and any associated baffle structure. In the ocean, however, backscattering from various discontinuities contributes significantly to thein situminor‐lobe structure. One type of practical discontinuity in the ocean is that caused by volume scatterers. It is of interest to examine theoretically the seriousness of volume scattering as a contribution to minor‐lobe level, since it would appear to impose a practical limit to what can be achieved by minor‐lobe‐suppression techniques in hydrophone design. Quantitative deductions concerning this phenomenon may be made regarding the effects of such factors as volume‐scattering coefficient, direction of source, distance to source, directivity index of hydrophone, and attenuation constant of the medium.

ISSN:0001-4966    

DOI:10.1121/1.1930016

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

This paper describes a new instrument called a strobolyzer which makes it possible to observe, in slow motion, the vibrations of any body at any audio‐frequency even though the amplitude of motion is microscopic. It can be used to determine resonant modes of complicated bodies or to observe changes in motion as changes are made in frequency, loading, or driving point. The motion to be studied is detected by a number of vibration pickups placed to show the interesting features of the motion. The signal from each pickup is at the vibrating frequency but, in general, will differ from the other pickup signals in amplitude and phase. In the strobolyzer, the signal from each pickup is mixed with a common signal which differs by a small amount, Δcps, from the vibrating frequency. The signals from the mixer, after filtering, are at Δcps and the amplitude and phase relations which exist among the signals from the pickups are preserved in the signals from the mixers. The signal from each mixer drives an indicator which is mounted on a rough model of the vibrating body in a position which corresponds to the respective pickup.

ISSN:0001-4966    

DOI:10.1121/1.1930025

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

The electrostatic uniangular microphone consists of an electrostatic transducer combined with an acoustical network to provide a uniform response with respect to frequency and a uniangular directivity pattern. The microphone exhibits a high order of directivity. The polar directional pattern is independent of the frequency.

ISSN:0001-4966    

DOI:10.1121/1.1930029

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

A novel principle has been developed, applicable to folded horns, for improving the acoustic transmission around bends having a radius greater than one quarter wavelength. This consists of the use of a conoidal reflecting‐type surface in the outer half of the fold. It is beneficial in the frequency‐spatial region intermediate between normal horn refraction action and specular or optical‐type reflection. A practical application is described.

ISSN:0001-4966    

DOI:10.1121/1.1930035

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

Endolymphatic oxygen tension, action potential, and microphonics were recorded simultaneously and continuously from the first turn of the cochlea of guinea pigs during and following acute asphyxia, loud sounds, and chronic hypoxia. The curves thus obtained will be compared. Endolymphatic hypoxia of the order of that induced by a loud sound produces marked changes in action potential and microphonics. These results will be discussed in terms of hypoxia playing an important role in the temporary hearing loss induced by loud sounds.

ISSN:0001-4966    

DOI:10.1121/1.1930043

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

Up to recent times acoustics was primarily concerned with small amplitude irrotational motion of a compressible medium and fluid mechanics dealt with incompressible flow, consequently there was no overlapping area between those two disciplines. Presently, however, the importance of understanding both compressible flow and large amplitude waves in the presence of important viscous and heat conduction effects created a real need for a single unified discipline that includes both small amplitude irrotation waves and incompressible flow as special limiting cases. The full Navier‐Stokes equations of a viscous heat conductive gas are strongly nonlinear. For weak fields, however, the solutions reduce to three independent “modes” and those can be identified as vorticity, sound waves, and entropy spots. A second‐order theory indicates interaction between all the modes and the familiar examples such as sound generation by vorticity, sound scattering on entropy nonuniformities, heat convection by turbulence, etc., can all be accounted for by a single unified theory.

ISSN:0001-4966    

DOI:10.1121/1.1930046

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

In an attempt to understand some of the physical processes involved in the interaction between helium driven shock waves in argon and powdered solids, microscopic, x‐ray, and chemical techniques have been employed in conjunction with the spectroscopic observations to study the changes in grain surfaces before and after shock treatment. The shock wave particle interaction has many points of similarity to that of the traversal of a meteoroid through the upper atmosphere and, as expected, evidence of severe surface ablation has been noted in many cases. In some, interesting surface chemical changes have occurred (e.g.,Fe2O3 → Fe3O4) and in others [AgCN,Fe3Co(CN)6] the formation of carbon, as soot particles, has been correlated with the spectra.

ISSN:0001-4966    

DOI:10.1121/1.1930050

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP

摘要:

The response of structures to random vibration is discussed in terms of the damage producing characteristics of the response. Various damage processes both in the structure and in components mounted on the structure are then considered, and means for alleviating the damage are discussed. This leads to some simple statements of criteria for minimum damage in different cases, and some practical suggestions on how this may be achieved.

ISSN:0001-4966    

DOI:10.1121/1.1930057

出版商:Acoustical Society of America    

年代:1958

数据来源: AIP