The bandwidth in an acoustic acquisition system is limited by the hydrophone bandwidth, the analog input bandwidth and the sampling rate of the system. By default we use hydrophones that have a bandwidth exceeding 150 kHz, and an analog bandwidth out to about 160 kHz. We use a fixed sampling rate of 768 kHz on our analog to digital converters so this entire bandwidth is adequately sampled. Changes in sample rates are done in the digital domain using digital filtering and decimation techniques.
Typical bandwidth is therefore out to about 150 kHz when using the 384 kHz sampling rate mode. This wide bandwidth allows the user to capture not only audible underwater noise, but sources well into the ultrasonic spectrum, including dolphin and porpoise clicks, sonar signals from vessels and a variety of commercial fish tags.