IEC 60565-1-2020 pdf free download – Underwater acoustics – Hydrophones – Calibration of hydrophones – Part 1: Procedures for free-field calibration of hydrophones
This part of IEC 60565 specifies methods and procedures for free-field calibration ofhydrophones, as well as individual electroacoustic transducers that can be used ashydrophones (receivers) and/or projectors (source transducers). Two general types ofcalibration are covered within this document: absolute calibration using the method of three-transducer spherical-wave reciprocity, and relative calibration by comparison with a referencedevice which has already been the subject of an absolute calibration.
The maximum frequency range of the methods specified in this document is from 200 Hz to1MHz.The lowest acoustic frequency of application will depend on a number of factors,andwill typically be in the range 200 Hz to 5 kHz depending mainly on the dimensions of the chosentest facility,The highest frequency of application for the methods described here is 1 MHz.
Procedures for pressure hydrophone calibration at low frequencies can be found inIEC 60565-2[1]1.Procedures for hydrophone calibration at acoustic frequencies greater than1 MHz are covered by lEC62127-2[2].
Excluded from the scope of this document are low-frequency pressure calibrations ofhydrophones, which are described in lEC 60565-2[1].Also excluded are calibrations of digitalhydrophones and systems,calibration of marine autonomous acoustic recorders, calibrationof acoustic vector sensors such as particle velocity sensors and pressure gradienthydrophones,calibration of passive sonar arrays consisting of multiple hydrophones,andcalibration of active sonar arrays consisting of projectors and hydrophones.
This document presents a description of the requirements for free-field calibration in terms oftest facility,equipment and instrumentation,signal processing,and frequency limitations.Adescription of achievable uncertainty and rules for the presentation of the calibration data areprovided.Also included are informative annexes that provide additional guidance on
• measurement of directional response of a hydrophone or projector,
• measurement of electrical impedance of hydrophones and projectors,
• electrical loading corrections,
• acoustic far-field criteria in underwater acoustic calibration,
• pulsed techniques in free-field calibrations,
• assessment of uncertainty in the free-field calibration of hydrophones and projectors,
• derivation of the formulae for three-transducer spherical-wave reciprocity calibrations,
• calibration using travelling-wave tubes,
• calibration of hydrophones using optical interferometry, and
• calibrations in reverberant water tanks using continuous signals.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document.For dated references, only the edition cited applies.For undated references,the latest edition of the referenced document (including anyamendments) applies.
IEC 60050-801,International Electrotechnical Vocabulary – Chapter 801: Acoustics andelectroacoustics (available at http://www.electropedia.org/)
IEC 60500:2017, Underwater acoustics – Hydrophones – Properties of the hydrophone in thefrequency range 1 Hz to 500 kHz
3Terms and definitions
For the purposes of this document,the terms and definitions given in IEC 60050-801,IEC 60500:2017 and the following apply.
ISo and lEc maintain terminological databases for use in standardization at the followingaddresses:
IEC Electropedia: available at http://www.electropedia.orgl
Iso Online browsing platform: available at http://www.iso.orglobp
3.1
acoustic far-field
sound field at a sufficient distance from a sound source in a uniform medium where the soundpressure and sound particle velocity are substantially in phase and the direct-path soundpressure amplitude, compensated for absorption loss,varies inversely with distance
Note 1 to entry: The range (distance from the source) is taken along a direct path between the source and thereceiver.
Note 2 to entry: The inverse dependence on range does not imply that the source radiates equally in all directions.[SOURCE: IEC 60050-801:1994,801-23-30， modified – In the definition, “and the direct-pathsound pressure amplitude, compensated for absorption loss, varies inversely with distance” hasbeen added, sourced from lso 18405:2017,3.3.1.1.]IEC 60565-1 pdf download