摘要:

The use of the cepstrum method for signal arrival times extraction of overlapping signals due to multipath conditions in shallow water is considered. The cepstrum method is applied to signal data from a research cruise. The results fall in two parts: (1) the use of a single cepstrum calculation will not clearly identify the different arrival times and (2) the use of several cepstrum calculations gives a consistant pattern of dominant peaks at or near the calculated arrival times. The assumption made in the cepstrum derivation that echoes are replicas of the first arrival is not correct.Subject Classification: [43]30.20; [43]60.30; [43]85.84.

ISSN:0001-4966    

DOI:10.1121/1.380849

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

The problem of correlating the incidence of Raynaud’s phenomenon with exposure to a given vibration environment is well known. It is hypothesized that energy absorbed and dissipated in the hand is energy which can change hand tissue in some manner, and thus may cause injury. Absorbed power is therefore suggested as a parameter which has potential for evaluation of individual worker susceptibility to vibration injury. The arm is represented as a foundation with finite mechanical impedance for the hand model. The hand model parameters, obtainable from experimental impedance measurements on individual subjects, are assumed to be, in general, frequency dependent. The total impedance expression for the system is generalized for the case where the hand is gripping a vibrating handle covered with a layer of viscoelastic material. An expression for absorbed power in this composite system exposed to random vibration is presented.Subject Classification: [43]40.45.

ISSN:0001-4966    

DOI:10.1121/1.380850

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

An orthogonality relation for the Rayleigh‐Lamb modes of vibration of an isotropic, homogeneous, elastic plate is derived.Subject Classification: [43]40.24.

ISSN:0001-4966    

DOI:10.1121/1.380851

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Reports from this and other laboratories are summarized to the effect that pulse trains in the 3–4‐kHz region, with pulse duration ?1 sec and with on fractions up to 0.05, are habitable when presented a round the clock for weeks, and yield no TTS greater than can be borne, when the level does not exceed 85 dB SPL. For more onerous acoustic loads, a damage risk criterion of 80 dB should be set for long‐lasting continuous exposures. The ear is more susceptible to this sort of acoustic load than is any other system of the body, and can serve as an early warning device for potential damage to those systems.Subject Classification:[43]65.50,[43]65.64, [43]65.66.

ISSN:0001-4966    

DOI:10.1121/1.380852

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Searleetal. [J. Acoust. Soc. Am. 57, 448–455 (1975)] conclude that disparities between right and left pinna filtering are used as median‐plane localization cues. Their experiments fail to separate elevation cues due to pinna disparities from elevation cues due to binaural IAD and ITD information caused by slight misalignment of subjects’ heads with the median plane defined by the sound source.Subject Classification: [43]65.62, [43]65.20.

ISSN:0001-4966    

DOI:10.1121/1.380853

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Monaural loudness adaptation was measured in subjects with normal hearing and in subjects with noise‐induced sensori‐neural hearing loss using a dichotic delayed balance procedure. Adapting stimuli were presented at two sensation levels (15 and 25 dB SL), two frequencies (500 and 4000 Hz), three durations (1, 30, and 60 sec) and two inter‐stimulus intervals (10 and 400 msec) and the loudness of the terminal portion of the adapting stimuli was measured with a method of constant stimuli. No loudness adaptation occurred under any conditions for the normal subjects. Hearing‐impaired subjects demonstrated small amounts of loudness adaptation, but the occurrence of adaptation did not always coincide with the frequency region of the hearing loss. There was no effect of interstimulus interval for either subject group.Subject Classification: [43]65.50, [43]65.64, [43]65.66.

ISSN:0001-4966    

DOI:10.1121/1.380854

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Loudness‐adaptation measurements were made using a monaural procedure at 10‐, 20‐, and 40‐dB SL for 500 and 4000 Hz in six subjects with noise‐induced hearing loss. The results indicated loudness adaptation only for 10‐dB SL at 4000 Hz (where hearing loss was present) and for only three of the subjects. The findings support similar data obtained using dichotic (heterophonic) loudness‐balance and threshold tone‐decay techniques.Subject Classification: [43]65.50, [43]65.64; [43]50.70.

ISSN:0001-4966    

DOI:10.1121/1.380855

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Recordings were made of nine subjects producing test words in seven different styles, varying from completely informal conversation to reading the test words in lists. The subjects were all educated male speakers of standard English who had lived in Southern California from an early age. The data were analyzed using a computer system that determined the frequency, amplitude, and intensity of the first four formants. It was found that the nucleus of the vowel was not affected by differences in the style of speech.Subject Classification: [43]70.40, [43]70.65.

ISSN:0001-4966    

DOI:10.1121/1.380856

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

An experiment for an advanced undergraduate or graduate laboratory in acoustics is descrived. The temperature dependence of the driving‐point impedance curve of a hairpin magnetostrictive‐stack transducer was measured in the temperature range 25 °C down to liquid‐nitrogen temperature.Subject Classification: [43]85.20, [43]85.40; [43]10.85.

ISSN:0001-4966    

DOI:10.1121/1.380857

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

ISSN:0001-4966    

DOI:10.1121/1.381037

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP