摘要:

A theoretical discussion is given of optical telephone receivers employing the optoacoustic effect, which are here called photophones, for use in an optical‐fiber telephone subscriber loop. The basic receiver consists of an absorption cell, a response‐equalizing device such as a gas column or diaphragm, a tapered acoustic tube acting as a transformer, and an earpiece similar to a conventional telephone earpiece including a response‐equalizing device. These photophones are designed to give a flat (3‐dB) response to intensity modulated light over the telephone voice band 300–3300 Hz. The optoacoustic effect is treated on the basis of a pseudogas model for solid absorbers in the form of a fine mesh disbusrsed in a gas. We find that the sensitivity (the optical power modulation required to produce a sound pressure level SPL = 81 dB in a closed volume of 6 cm3, representing the earpiece pressed against the ear) is 2.8 and 0.9 mW for the air‐filled and xenon‐filled photophones, respectively.Subject Classification: [43]85.76, [43]85.40, [43]85.60; [43]35.65.

ISSN:0001-4966    

DOI:10.1121/1.380991

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Subject Classification: [43]20.30, [43]20.55; [43]28.20.

ISSN:0001-4966    

DOI:10.1121/1.380992

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

The effect of duch Mach number upon the acoustic reflection coefficient at the inlet of a duct with mean flow is investiagted. An analysis, which models the duct inlet as a very short, one‐dimensional nozzle over which the mean flow is accelerated from rest, gives good agreement with some recent experimental results. Discrepancies between the analysis and he experimental results are discussed in terms of radiation losses at the inlet and real fluid‐flow effects within the duct.Subject Classification: [43]28.60; [43]20.30.

ISSN:0001-4966    

DOI:10.1121/1.380993

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

The surface reflection loss suffered by refracted‐surface‐reflected rays is formulated asymptotically for long‐range transmission. Like the absorption loss, it is proportional to range and to frequency squared.Subject Classification: [43]30.20, [43]30.25, [43]30.30.

ISSN:0001-4966    

DOI:10.1121/1.380994

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

The transmission loss of an acoustic plane wave through a steel plate in water has been computed using Timoshenko–Mindlin plate theory and exact elasticity theory. Good agreement between the two models is found up to a frequency–thickness product of 20 kHz in. At 40 kHz in. and above, limitations of the plate theory approach become apparent.Subject Classification: [43]30.50; [43]20.60; [43]40.24; [43]20.30.

ISSN:0001-4966    

DOI:10.1121/1.380995

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

The expression and numerical results in the original letter were based on the use of Timoshenko–Mindlin plate theory and thus have an inherent frequency–plate‐thickness limitation when compared to results based on the use of elasticity theory. This limitation, which is noted by Young, was already noted, however, in the concluding section of the original letter. In addition it is noted that the second acoustic coincidence lobe was not attributed in the original letter to a dilatational mode, but was attributed to a flexural wave whose phase velocity at high frequencies approaches the velocity of a dilatational wave in an infinite elastic medium.Subject Classification: [43]30.50; [43]20.60; [43]40.24; [43]20.30.

ISSN:0001-4966    

DOI:10.1121/1.380996

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

The free vibration problem of unstressed and stressed generally orthotropic skew plates using an integral equation approach is considered by Srinivasan and Ramachandran [J. Acoust. Soc. Am. 57, 1113–1118 (1975)]. Some comments on the convergence aspects of their results are offered here. Also, certain features of the nodal patterns and frequency plots are discussed.Subject Classification: [43]40.24.

ISSN:0001-4966    

DOI:10.1121/1.380997

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Subject Classification: [43]40.24.

ISSN:0001-4966    

DOI:10.1121/1.380998

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Coats (1974) investigated the effects of different electrode contact‐points in recording the electrocochleograhic (ECochG) response of humans. He recorded from a needle electrode positioned at various places within the ear canal, from a specially fabricated intra‐auricular electrode, and from an earlobe clip. He concluded that the earlobe‐clip electrode was unsatisfactory for ECochG recording. Evidence is presented contrary to his conclusion, as it is demonstrated that the earlobe‐clip electrode in combination with a more distant electrode is a satisfactory method for obtaining the ECochG response.Subject Classification: [43]65.80; [43]85.92.

ISSN:0001-4966    

DOI:10.1121/1.380999

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP

摘要:

Data from 15 modern studies are used to characterize the deviations from Weber’s law for intensity discrimination of 1000‐Hz tone pulses. The results show that Weber’s law is satisfied in the region 10–40 dB SL, that resolution descreases with decreasing intensity below 10 dB SL and increases with increasing intensity above 40 dB SL, and that resolution at 90 dB SL is roughly 2.5 times better than at 40 dB SL.Subject Classification: [43]65.50, [43]65.75.

ISSN:0001-4966    

DOI:10.1121/1.381000

出版商:Acoustical Society of America    

年代:1976

数据来源: AIP