IEC 62127-2:2025 specifies:
- absolute hydrophone calibration methods;
- relative (comparative) hydrophone calibration methods.
Recommendations and references to accepted literature are made for the various relative and absolute calibration methods in the frequency range covered by this document.
This document is applicable to
- hydrophones used for measurements made in water and in the ultrasonic frequency range 50 kHz to 100 MHz;
- hydrophones employing piezoelectric sensor elements, designed to measure the pulsed wave and continuous wave ultrasonic fields generated by ultrasonic equipment;
- hydrophones with or without a hydrophone pre-amplifier.
IEC 62127-2:2025 cancels and replaces the first edition published in 2007, Amendment 1:2013 and Amendment 2:2017. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) the upper frequency limit of 40 MHz has been removed;
b) hydrophone sensitivity definitions have been changed to recognize sensitivities as complex-valued quantities;
c) directional response measurement and effective size determination procedures have been updated in 12.5.1 to align with recent changes in IEC 62127-3;
d) Annex F has been amended to comprise a calibration technique for high-frequency complex-valued calibration;
e) the reciprocity method description in Annex K was extended to also comprise focusing transducers.