This standard specifies the main performance parameters and other technical requirements of piezoelectric standard hydrophones used as measuring instruments in the frequency range of 1 to 10 MHz. This standard is applicable to the quality evaluation of standard hydrophones for hydroacoustic and ultrasonic measuring instruments manufactured by manufacturers. GB/T 4128-1995 Acoustic Standard Hydrophone GB/T4128-1995 Standard download decompression password: www.bzxz.net
This standard specifies the main performance parameters and other technical requirements of piezoelectric standard hydrophones used as measuring instruments in the frequency range of 1 to 10 MHz. This standard is applicable to the quality evaluation of standard hydrophones for hydroacoustic and ultrasonic measuring instruments manufactured by manufacturers.

National Standard of the People's Republic of China
Acoustics-Standard Hydrophone
Acoustics-Standard HydrophoneCB/T 4128—1995
Recommended GB 4128—-B4
This standard adopts IEC5001974 "Standard Hydrophone" and IEC866:1987 "Characteristics and Calibration Methods of Hydrophones in the Frequency Range of 0.5~15MHz".
1 Subject Content and Scope of Application
This standard specifies the main performance parameters and other technical requirements of piezoelectric standard hydrophones used as measuring instruments in the frequency range of 1~10 MHz.
This standard is applicable to the quality evaluation of standard hydrophones of hydroacoustic and ultrasonic measuring instruments manufactured by manufacturers. 2 Reference standards
GB3228 Free-field calibration method for underwater acoustic transducers GB3947 Acoustic terminology
GB4130 Low-frequency pre-calibration method for hydrophonesbZxz.net
GB/T15611 Calibration method for high-frequency hydrophones 3 Terminology
The acoustic terms used in this standard are in accordance with the provisions of GB3947. 4 Classification
4.1 Divided into two levels according to the purpose of use and calibration uncertainty. 4.1.1 Standard hydrophones (also called primary standard hydrophones) are used as metrological standard instruments or for precise acoustic measurements. Such hydrophones should be calibrated using the absolute calibration methods specified in GB3223, GB4130 and GB/T15611. 4.1.2 Measuring hydrophones (also called secondary standard hydrophones) are used as working metrological instruments. Such hydrophones should be calibrated using the comparative calibration methods specified in GB3223 and GB4130. 4.2 Divided into two sections according to the frequency range
4.2.1 [Low frequency] The frequency range of hydrophone is 1Hz~100kH. In the past, low frequency hydrophone can be referred to as hydrophone when it does not cause mixing. 4.2.2 The frequency range of high frequency hydrophone is 0.1~10MHz. 5 Main performance parameters
The technical indicators of the main performance parameters specified in this standard should be measured under the environmental conditions of water temperature 5~30℃ and water depth Q~10m. And the actual measurement environmental conditions should be given.
5.1 [Low-frequency] Hydrophone
5.1.1 [Low-frequency standard hydrophone
Approved by the State Administration of Technology on July 3, 1995
Implementation on February 1, 1996
5. 1. 1. 1 Sensitivity [level]
GB/T 4128--1995
The sound pressure sensitivity or low-frequency free-field sensitivity should not be less than -205dB (0dB ≥ 1V/μPa). Note:) The low-frequency free-field sensitivity refers to the average value of the free-field sensitivity of the particle response curve. (2 The sensitivity here refers to the open circuit voltage sensitivity. 5.1.1.2 Free field sensitivity frequency response In the entire frequency range of use, there are at least three decades of range, and the non-uniformity of free field sensitivity should be less than ±1.5dB. 5.1.1.3 Directivity
Horizontal directivity: The -3dB beam width at the highest frequency of use should be greater than 30°. Within the range of ±5° of the selected direction (or main axis), the sensitivity change should be less than ±.dB. b. Vertical directivity: The -3dB beam width at the highest frequency of use should be greater than 15. Within the range of ±2° of the selected direction (or main axis), the sensitivity change should be less than ±0.2 dB. 5.1.1. 4 Dynamic range
Within the dynamic range of 60 dB, the output voltage of the hydrophone shall be linearly related to the free-field sound pressure, and the deviation shall be less than ±0.5 dB. 5.1.1.5 Stability
Temperature stability: Within the working temperature range of 0 to 40 °C, the deviation of the sensitivity from the sensitivity at 23 °C shall not exceed 0.04 dB/c.
Static pressure stability: Within the water depth of 0 to 100 m, the change in sensitivity shall not exceed 0.3 dB/MPa. c. Time stability: Within the calibration period of one year, the change in sensitivity shall not exceed ±0.7 dB. 5.1.2 Low-frequency measurement hydrophone
5.1.2.1 Sensitivity [Level]
The sound pressure sensitivity or low-frequency free-field sensitivity shall not be less than -210 dB (0 dB = 1 V/μPa). Note: See Notes (1) and 2) of 5.1.1.1. 5.1.2.2 Free-field sensitivity frequency response
In the entire frequency range of use, there are at least three decades of frequency range, and the non-uniformity of free-field sensitivity should be less than ±2 dB. 5.1.2.3 Inter-finger directivity
Horizontal directivity: It should be omnidirectional within the frequency range of use, and the deviation of its directivity diagram from the ideal omnidirectional directivity diagram should be less than ±2 dB.
h Vertical directivity: The 3dB beam width at the highest frequency should be greater than 30° 5.1.2.4 Dynamic range
Within the dynamic range of 60 dB, the output voltage of the hydrophone should be linearly related to the free-field sound pressure, and its deviation should be less than ±1 dB. 5.1.2.5 Stability
Temperature stability: Within the operating temperature range of 0 to 4U'C. The sensitivity change should not be greater than 0. U5 dB/℃. b. Static pressure stability: Within the water depth of 0 to 100 m, the change in sensitivity should not exceed 0.4 dB/MPa. c. Time stability: Within the calibration period of one year, the change in sensitivity should not exceed ±1.5 dB. 5.2 High frequency hydrophone
5.2.1 High frequency standard hydrophone
5.2.1.1 Sensitivity level
The sensitivity should not be less than -265 dB (0 dB≤1V/rPa). Note: This sensitivity is the average value of the free field sensitivity response curve and the positive sensitivity of the parallel circuit. 5.2.1.2 Free field sensitivity frequency response
In the entire operating frequency range, there should be at least 2 times the range, and the non-uniformity of the free field sensitivity should be less than ±2 dB. And the change in sensitivity should be less than ±0.5 dB for every 100kHz change in frequency. 5-.2.1.3 Directivity
GB/T41281995
a. Effective solid angle: At the highest frequency of use, the beam width of -6dB should be greater than 15°. b. Beam symmetry Within the effective solid angle, the asymmetry of the beam should be less than ±3 dB. c. The deviation between the direction of maximum sensitivity and the direction of the axis of symmetry should be less than 3°5.2.1.4 Dynamic range
In the dynamic range of 40dB, the output voltage of the hydrophone should be linearly related to the free field sound pressure, and its deviation should be less than ±1dB. Under the condition that the signal-to-noise ratio is greater than 6 dB, the minimum sound pressure level that can be measured should not be less than 190 dH (0dB≥1 μPa). 5.2. 1. 5 Stability
a. Temperature stability: Within the range of 16-30°C, the deviation of sensitivity from the sensitivity at 23°C should not be greater than ±1 dB; within the range of 30-40°C, the deviation of sensitivity from the sensitivity at 23°C should not be greater than ±2 dB. b. Time stability: Within the calibration period of one year, the change in sensitivity should not be greater than ±2 dB. 5.2.2 High frequency hydrophone
5.2.2.1 Sensitivity [level]
The sensitivity should not be less than f-270dB (0dH ≥ 1V/μPa). Note: See the note of 5.2.1.1
5.2.2.2 Free field sensitivity frequency response
The range of the free field sensitivity is less than ±4 dB, and the change in sensitivity should be less than ±1 dB for at least 2 times the frequency within the entire operating frequency range, and the change in sensitivity should be less than ±1 dB for every 100kHz change of the frequency. 5.2.2.3 Directivity
Same as the provisions of Article 5.2.1.3.
5.2.2.4 Dynamic range
Same as the provisions of Article 5.2.1.4.
5.2.2.5 Stability
a. Temperature stability: Within the range of 16-30°C, the deviation of sensitivity from the sensitivity at 23°C should not be greater than ±1.5 dB; within the range of 30-40°C, the deviation of sensitivity from the sensitivity at 23°C should not be greater than ±3 dB. b. Time stability: Within the calibration cycle of one year, the change in sensitivity should not be greater than +3 dB. 6 Other technical requirements
6.1 Mechanical performance requirements
6.1.1 All metal and non-metal parts of the hydrophone exposed to water should be made of corrosion-resistant materials. 6.1.2 The reference sound center position and reference direction of the hydrophone should be clearly marked. 6.1.3 The surface of the hydrophone in contact with water should be smooth, non-porous and wettable. 6.2 Electrical performance requirements
6.2.1 For low frequency hydrophones without preamplifiers, the insulation resistance measured at the cable end shall be greater than 100Ω (test voltage not less than 100V). For high frequency hydrophones, the insulation resistance shall be greater than 100k. 6.2.2 High impedance sensitive components shall have electrostatic shielding, and the electrostatic shielding and the metal shell of the hydrophone exposed to water shall be connected to the cable shielding
6.2.3 The connection shielding cable of the low impedance hydrophone shall be not less than 10m. 6.2.4 When the capacitance of the inductive component is smaller than the capacitance of the connecting cable, it can be connected to the preamplifier. The length of the connecting cable between the hydrophone and the preamplifier is given by the manufacturer. A1 Hydrophone without preamplifier
Sensitivity (grade)
GB/T 4128—1995
Appendix A
Data provided by the manufacturer
(Test items)
dB (QdB≤1 V/μPa);
Frequency range and average frequency response range and frequency response curve Capacitance at the end of the cable pF;
Insulation resistance at the end of the cable (DC) $2:
Give at least four typical frequencies (including the highest frequency of use) horizontal and vertical directivity diagrams: The reference sound center position and the measurement direction should be clearly marked on the shell of the hydrophone. The name and model of the sensitive component material;
The location of the sensitive component and the size of the component; Show the cable wiring diagram:
Exposed metal in contact with the liquid Name and model of materials; Name and model of jacket or covering materials in contact with liquid, Cable length
Not including the cable's dimension
Weight when including the cable
Working temperature range
Temperature stability
Maximum working depth
Static pressure stability
Storage conditions:
Time stability
dB or dB/C;
Hydrophone with preamplifier
Hydrophone system
Sensitivity (level]
dB (0 dB≤IV/μPa);
Frequency range and average frequency response range Frequency characteristic curve of equivalent noise pressure spectrum level of sound response curve Overload sound pressure level
dB (0 dH≤1 μPa):
Capacitance of hydrophone head
dB
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