Coupler-Reciprocity System for Hydrophone Calibration at High Pressures

McMahon, G. W.

doi:10.1121/1.1919356

Cited by 7 publications

(5 citation statements)

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“…To correctly obtain the sensitivity of hydrophones in the deep ocean with high hydrostatic pressure, many measurement methods and facilities have been performed all over the world. The most widely used method is the coupler reciprocity method in a low-frequency range below 2 kHz [3][4][5][6]. In addition, the ocean simulation and acoustic calibration vessel were established in the Underwater Sound Reference Division (USRD) [7, IOP Publishing doi:10.1088/1742-6596/2756/1/012044 2 8].…”

Section: Introductionmentioning

confidence: 99%

Free-field three-transducer spherical-wave reciprocity calibration for hydrophone at hydrostatic pressure of 10 MPa

Jia,

Chen,

Zhang

2024

J. Phys.: Conf. Ser.

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Free-field three-transducer spherical-wave reciprocity method has been reviewed and employed to calibrate the hydrophone of TC4033 in a high hydrostatic pressure vessel. To reduce the measurement uncertainty, a reciprocal calibration bracket and reciprocal transducers were designed and developed. The calibration bracket can locate the transducers in the high hydrostatic pressure vessel. The reciprocal transducer can reduce the errors caused by the deviation of reciprocity. A correcting sensitivity method based on complex electrical impedance measurement has been described, which can obtain the original open-circuit sensitivity of a hydrophone. It is more accurate than correcting method based on the measurement of extension cable capacitance especially near the resonant frequency range. The TC 4033 hydrophone was calibrated in the one-third octave frequency points from 2 kHz to 200 kHz at a high hydrostatic pressure of 10 MPa. The calibration results were analyzed, and the measurement uncertainty was estimated to be 0.5 dB (k=2).

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Section: Introductionmentioning

confidence: 99%

Free-field three-transducer spherical-wave reciprocity calibration for hydrophone at hydrostatic pressure of 10 MPa

Jia,

Chen,

Zhang

2024

J. Phys.: Conf. Ser.

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“…As an alternative to free field calibration in an acoustical water tank, a number of different methods for low frequency calibration of hydrophones exist. These include calibration by piezoelectric compensation, 3 acoustic coupler reciprocity calibration 4 and calibration with a pistophone. 5 In the piezoelectric compensation method, the hydrophone is calibrated in an enclosed small water-filled chamber.…”

Section: Introductionmentioning

confidence: 99%

“…Acoustic coupler reciprocity calibration is an absolute calibration method using the reciprocity principle. 4 Though laboratory standard hydrophones may be calibrated with the highest accuracy, the coupler is not a good option to calibrate hydrophones that are large or to calibrate hydrophones near the resonance frequency. In a pistophone, a continuous sound pressure is generated in an enclosed small air-filled chamber by a vibrating piston.…”

Section: Introductionmentioning

confidence: 99%

“…7 Strasberg et al explained several advantages calibrating the pressure gradient hydrophones in a cylinder of liquid, wherein they are subjected to axial vibration (as opposed to horizontal orientation of the cylinder). 4 In the vibrating water column method, the hydrophone under calibration is immersed in a water column; the position of the transducer is kept constant while the fluid column is moved sinusoidally. Schloss et al used the vibrating water column method for the calibration of hydrophones, wherein the cylinder is placed over the vibrating shaker and half the cylinder is filled with water.…”

Section: Introductionmentioning

confidence: 99%

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Design Considerations and Establishment of a Low Frequency Hydrophone Calibration Setup using the Principle of Vibrating Water Column

Malarkodi¹,

Latha²,

Sridhar³

et al. 2018

IJAV

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This paper describes the design and implementation of a low frequency hydrophone calibration system, using a vibrating water column. The hydrophone to be calibrated is immersed in the water column and the position of the transducer is kept constant while a hydrodynamic pressure field is generated in the water column by means of a shaker (similar to what is described in IEC 60565). F. Schloss et al. used a vibrating water column for hydrophone calibration in the frequency range from 10 Hz to 700 Hz. 1 An interlaboratory comparison calibration was carried out by the Russian Metrological Institute of Technical Physics and Radio Engineering (VNIIFTRI) and Hangzhou Applied Acoustics Research Institute (HAARI) in the frequency range from 250 Hz to 1 kHz. 2 The dimensions of the test vessel are important for deciding the frequency range of operation. Simulations were carried out for the selection of vessel material and dimension. To overcome limitations in the frequency range caused by resonance in the water column, the principle of operation was modified from absolute calibration to calibration by comparison. By using a single cylindrical vessel, the frequency range is extended to cover frequencies from less than 100 Hz to 1 kHz. The calibrated reference hydrophone type Bruel & Kjaer (B&K) 8104 is used in this calibration. Some results obtained from the use of the calibration system are also presented in this paper.

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“…Coupler reciprocity calibrations are historically performed measuring only magnitude [1,3], and [4]. Phase response is more difficult to measure accurately and can be assumed constant when hydrophones are operating well below their resonance frequencies and, for hydrophones with preamplifiers, above their low-frequency cutoff.…”

Section: Introductionmentioning

confidence: 99%

A primary method for the complex calibration of a hydrophone from 1 Hz to 2 kHz

2017

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Considerations for a new high-accuracy transfer-coupler reciprocity system for absolute electro-acoustic calibration J F Zalesak IntroductionPrimary calibrations of hydrophones at frequencies less than about 1 kHz are typically performed in a coupler reciprocity chamber ('coupler'). The closed and controlled environment in the coupler allows for the performance of primary calibrations over the temperature and hydrostatic pressure range found in the ocean. The coupler reciprocity chamber is designed together with a primary reference standard hydrophone and two other reciprocal transducers because the volume and stiffness of the closed coupler system must be known precisely.The Underwater Sound Reference Division (USRD), a laboratory within the US Navy's (USN) research and development enterprise, provides metrology services related to underwater sound in the United States, including device calibration and leasing of underwater transducers, hydrophones, and projectors. Primary standards are maintained in-house. A coupler reciprocity system provides the primary standard calibration for frequencies less than 2 kHz [1]. The primary reference standard hydrophone is the USRD type H48 [2].To completely reproduce the acoustic waveform measured with a hydrophone, magnitude and phase information are required. Coupler reciprocity calibrations are historically performed measuring only magnitude [1, 3], and [4]. Phase response is more difficult to measure accurately and can be assumed constant when hydrophones are operating well below their resonance frequencies and, for hydrophones with preamplifiers, above their low-frequency cutoff. The type H48 reference is used well below it first resonance, but the low end of the frequency range can be affected by the low-frequency cutoff, problematic when secondary references are needed to measure frequencies below 5 Hz. Extending the coupler reciprocity calibration measurement to include phase is important to provide traceability for secondary references and to reduce AbstractA primary calibration method is demonstrated to obtain the magnitude and phase of the complex sensitivity for a hydrophone at frequencies between 1 Hz and 2 kHz. The measurement is performed in a coupler reciprocity chamber ('coupler'); a closed test chamber where time harmonic oscillations in pressure can be achieved and the reciprocity conditions required for a primary calibration can be realized. Relevant theory is reviewed and the reciprocity parameter updated for the complex measurement. Systematic errors and corrections for magnitude are reviewed and more added for phase. The combined expanded uncertainties of the magnitude and phase of the complex sensitivity at 1 Hz were 0.1 dB re 1 V µPa −1 and ±1• , respectively. Complex sensitivity, sensitivity magnitude, and phase measurements are presented on an example primary reference hydrophone.

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Coupler-Reciprocity System for Hydrophone Calibration at High Pressures

Cited by 7 publications

References 0 publications

Free-field three-transducer spherical-wave reciprocity calibration for hydrophone at hydrostatic pressure of 10 MPa

Free-field three-transducer spherical-wave reciprocity calibration for hydrophone at hydrostatic pressure of 10 MPa

Design Considerations and Establishment of a Low Frequency Hydrophone Calibration Setup using the Principle of Vibrating Water Column

A primary method for the complex calibration of a hydrophone from 1 Hz to 2 kHz

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