GB/T 4130.2-2024Acoustics - Calibration of hydrophones - Part 2: Procedures for low frequency pressure calibration (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for standardization work Part 1: Structure and drafting rules for standardization documents" Drafting.

This document is part 2 of GB/T 4130 "Calibration of acoustic hydrophones". GB/T 4130 has been published in the following parts.

--- Part 2: Low frequency sound pressure field calibration method.

This document replaces GB/T 4130-2017 "Low-frequency calibration method for acoustic hydrophones". Compared with GB/T 4130-2017, except for the structure in addition to adjustments and editorial changes, the main technical changes are as follows.

--- Added calibration steps (see Chapter 5);

--- Added electrical measurements (see Chapter 6);

--- Added the hydrostatic excitation method alternative (see 7.4);

--- Added pistonphone calibration (see Chapter 10);

--- Added static pressure transducer calibration (see Chapter 12);

--- Deleted the determination of hydrophone voltage coupling loss (see Appendix A of the 2017 edition);

--- Incorporate the determination of equivalent height into the hydrostatic excitation method calibration (see 7.2.3, Appendix B of the 2017 edition);

--- Incorporate the measurement method of the characteristic constants of the piezoelectric compensation transducer into the piezoelectric compensation method calibration (see 8.2.2, Appendix C of the 2017 edition).

This document is equivalent to IEC 60565-2:2019 "Hydroacoustics - Hydrophone calibration - Part 2: Low frequency sound pressure field calibration" step".

The following minimal editorial changes were made to this document.

--- In order to coordinate with the existing standards, the name of the standard is changed to "Acoustic hydrophone calibration part 2.low frequency sound pressure field calibration method";

--- Corrected the error in the original IEC text and moved the normative reference ISO/IEC Guide 98-3 from the references to Chapter 2.

Introduction

Hydrophones are used to convert underwater acoustic signals into electrical signals and are the core of sonar, underwater noise measurement systems, marine acoustic instruments and other equipment.

To ensure the accuracy and reliability of their measurement results, they need to be calibrated before use.

GB/T 4130 "Calibration of Acoustic Hydrophones" describes the calibration method of hydrophones, which aims to standardize and guide the calibration of hydrophones.

It consists of parts.

--- Part 1: Free-field calibration method. The purpose is to establish the free-field calibration of hydrophones and transducers in the frequency range of.200 Hz to 1 MHz.

Free-field calibration method.

--- Part 2: Low-frequency sound pressure field calibration method. The purpose is to establish the low-frequency sound pressure field calibration method of hydrophones in the frequency range of 0.01 Hz to several kilohertz.

Calibration method in high-frequency sound pressure field.

To ensure the accuracy of the calibration, the hydrophone to be calibrated should be a "rigid" hydrophone, which is small in size compared to the wavelength of the sound and Insensitive to vibration during calibration.

This document presents the hydrostatic excitation method, piezoelectric compensation method, acoustic coupling cavity reciprocity method, pistonphone method, vibrating liquid column method and hydrostatic transduction method.

The principles, steps and measurement uncertainty of physical calibration methods such as the hydrophone method. One of the above methods can be used to calibrate the hydrophone.

The choice depends on the principle used and the limitations of the sound field and frequency.

Acoustic Hydrophone Calibration Part 2: Low frequency sound pressure field calibration method

1 Scope

This document specifies the method for calibrating the low-frequency sound pressure field of a hydrophone in the frequency range of 0.01 Hz to several kilohertz. The calibrated frequency range depends on the depending on the calibration method used.

2 Normative references

The contents of the following documents constitute the essential clauses of this document through normative references in this document.

For referenced documents without a date, only the version corresponding to that date applies to this document; for referenced documents without a date, the latest version (including all amendments) applies to this document.

ISO/IEC Guide 98-3 Uncertainty of measurement Part 3: Guide to the expression of uncertainty in measurement Note. GB/T 27418-2017 Evaluation and expression of measurement uncertainty (ISO/IEC Guide 98-3..2008, MOD) Note. GB/T 2900.86-2009 Electrical terminology - acoustics and electroacoustics (IEC 60050-801:1994, IDT) IEC 60500:2017 Underwater acoustics - Hydrophones - Characteristics of hydrophones in the frequency range of 1 Hz to 500 kHz

3 Terms and definitions

For the purposes of this document, the terms and definitions defined in IEC 60050-801 and IEC 60500:2017 and listed below apply.

ISO and IEC maintain terminology databases used for standardization at the following URLs.

Coupler

A rigid fluid-filled cavity into which a transducer and a hydrophone can be inserted, the maximum dimension of the cavity being less than the wavelength.

NOTE. In this document, the term "small cavity" is used interchangeably with coupled cavity.

[Source. IEC 60565:2006[1], 3.3, modified] 3.2 Diffraction factor the root mean square value of the incident plane wave sound pressure from a given direction received by the hydrophone is equal to the value of the sound pressure at the reference center of the hydrophone after the hydrophone is removed.

The ratio of the free-field sound pressure to the RMS value.

Note. Perform spatial averaging first, then temporal averaging.

[Source. IEC 60500:2017, 3.3, modified]