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

Abstract

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.

New insight into contradictive relationship between sensitivity and working bandwidth of cilium MEMS bionic vector hydrophone

“…In practical application, the optimal structure is determined by the required working bandwidth to achieve the maximum sensitivity. For example, the frequency of 5-300 Hz could be widely used in national defense, oil, gas exploration and other fields [26]; the energy of marine environment sound is in the frequency of 20-1000 Hz [27]; some marine species, such as baleen whales [28] and C. ornatissimus [29], emit their noise in the frequency of 1000-2000 Hz. Moreover, the spectrum noise peak of vessel is in the frequency range from 100 Hz to 1 KHz [30].…”