The Sensitivity and Precision of the Electrostatic Transmitter for Measuring Sound Intensities

Wente, E. C.

doi:10.1103/physrev.19.498

Cited by 30 publications

(4 citation statements)

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“…The voltage on the input was then varied by means of the potentiometer, and the reading of the galvanometer was found to change, being greatest when maximum voltage was used and least when minimum was applied. This shows that the capacity of the condenser varies inversely as the applied voltage as stated by Wente and Crandall in the Physical Review for July, 1917, andJune, 1918.…”

supporting

confidence: 61%

Investigation of Resonance Curve with Respect to Variation of Capacity

Hudiburg¹

1931

Transactions of the Kansas Academy of Science (1903-)

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An investigation of the possibility of using a vibrating variable condenser in a Hartley Oscillator circuit to modulate the radio-frequency of the circuit, and a study of the effect of using the same type of condenser in a receiving circuit to modulate its radio-frequency. A receiving set in the form of a wave meter containing a variable condenser that may be made to vibrate at voice frequency is coupled inductively to a Hartley Oscillator and tuned to its frequency. It is found that the current in the wave meter fluctuates with the capacity change and that This shows that the effective current in an oscillatory circuit of extremely low resistance and operating near the peak of the resonance curve, may be controlled by the application of an audio-frequency variation of capacity. These results are, in form, very similar to those obtained with respect to the characteristic curve of a vacuum tube when changing the grid voltage. This makes 3 possible a system of modulation in which the radio-frequency changes according to the action of an audio-frequency control, but without change of amplitude, and without direct observance of the usual heterodyning rules of audio and radio frequencies. It is different from the ordinary type of modulation in which the audio-frequency is impressed upon the carrier wave as an envelope of the amplitude of the latter, and with the ordinary heterodyning rule of the addition and subtraction of the audio and radio frequencies.

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confidence: 61%

Investigation of Resonance Curve with Respect to Variation of Capacity

Hudiburg¹

1931

Transactions of the Kansas Academy of Science (1903-)

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“…This instrument could then be used to measure sound pressure. Wente used both a pistonphone and a thermophone to calibrate this microphone and a later improved one [9].…”

Section: Historical Background and Evolution Of Selected Primary Methodsmentioning

confidence: 99%

Brief review of primary methods applicable to key comparisons in acoustics

Nedzelnitsky¹

1999

Metrologia

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Historically, various techniques have been used in acoustics to attempt to establish and measure sound pressures (spatially uniform amplitude of sound pressure, as in a suitable coupling cavity that is small compared with a wavelength of sound) and in the free field (plane progressive sound wave at a specified angle of incidence, in the absence of reflecting surfaces). At present, over a broad range of frequencies the most accurate, precise, and convenient methods involve the primary calibrations of laboratory standard microphones by reciprocity techniques. Some issues and parameters in these techniques that must be considered in comparisons, and selected previous interlaboratory comparisons themselves, are discussed. Recommendations relevant to a key comparison already identified, as well as future work areas, are presented.

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“…Con el desarrollo del micrófono de , se abre el camino para el desarrollo de una tecnología propia de este tipo de transductores para uso científico. En 1922 publicó, para la American Physical Society, un artículo donde se definían las características técnicas de sensibilidad y precisión de los micrófonos de condensador [86]. Indicándose que la sensibilidad y precisión de las medidas se había ensayado durante un tiempo suficiente, permaneciendo constante ante las variaciones de presión, temperatura y humedad atmosférica en un ancho de banda comprendido entre 10 y 12000 Hz.…”

Section: 3-el Renacimiento El Nuevo Amanecer Para La Cienciaunclassified

Técnicas avanzadas de medida en intensimetría acústica para la caracterización de materiales aislantes

Saura¹

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Por último, el procedimiento ideado permitirá futuros desarrollos en el campo de la vibroacústica, tales como, la aplicación del principio de reciprocidad y la determinación de la impedancia acústica de materiales por técnicas de intensimetría acústica. ABSTRACTThe measurement rate of acoustic reduction (R) in an insulating material is determined in special designed enclosures according to UNE EN ISO 140-1 standard. The construction of a testing room that complies with the standards requires a significant financial investment, that too often can not be provided by general machinery manufacturers. The outdoor machines have to be designed considering the noise emission limits established in the European Directive 2000/14, making the installment of insulating materials in enclosures of machines necessary.Suppliers of insulating materials for industrial use does not normally provide the insulating properties of their products, which are often obtained from rock wool, polyethylene, polyurethane, synthetic rubber, etc. It is difficult to test these materials that are characterized by low density surface in a room standardized test procedure that is based on the measurement of sound pressure.The main problem is getting the validation of the measurement when the rate of acoustic reduction is relatively low, as in the case of materials mentioned above.An alternative procedure is proposed in this Doctoral Thesis based on the measurement of sound intensity. The vector nature of this parameter allows just the flow of energy through a given surface to be measured. The validation of the measurement is achieved with the highest degree of accuracy by applying the criteria included in the standard UNE EN ISO 9614. A steel plate 6 mm thick incorporated with a sound source for amplification of a pink noise signal is designed for carrying out the tests.

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The Sensitivity and Precision of the Electrostatic Transmitter for Measuring Sound Intensities

Cited by 30 publications

References 0 publications

Investigation of Resonance Curve with Respect to Variation of Capacity

Investigation of Resonance Curve with Respect to Variation of Capacity

Brief review of primary methods applicable to key comparisons in acoustics

Técnicas avanzadas de medida en intensimetría acústica para la caracterización de materiales aislantes

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