Developing a Low-Noise Data Acquisition System for Detection of Electric and Magnetic Fields in Seawater

摘要

The Office of Naval Research (ONR) has taken an interest in developing a modular electric and magnetic field sensor and acquisition system that can be mounted on a small autonomous underwater vehicle (AUV). In this thesis, a fully integrated data acquisition system is presented, achieving low power dissipation and low cost. Analog signal amplification uses instrumentation amplifiers due to their inherently low noise characteristics, high input impedance, and ease of gain adjustment. Signal conditioning circuitry is used to provide an acceptable voltage range for an analog to digital converter (ADC). A microcontroller is used to connect to the ADC to provide data buffering and retrieval capabilities. Connected to the microcontroller is a low-power microprocessor to handle higher level applications and data storage. In addition, silver-silver-chloride (Ag/AgCl) electrodes are used as the sensors to detect electric fields in seawater.