Design of analog-to-digital converter interface for hydrophone applications

Ship noise signature recognition needs a high dynamic range analog interface. We designed such interface connecting piezoelectric hydrophone to a PC. The design covers from signal conditioning preamplifier, ADC interfacing, to the acquisition software displaying a real-time frequency spectrum graph. DC-servo circuit was used in the preamplifier to address DC-offset issue inherent to piezoelectric hydrophones. A modified PCI sound card was used to transfer data from ADC to PC. The sound card CODEC was replaced by ADC being used. Tests were conducted in lab with a small-scale model.