| This dissertation addresses the design of a miniature acoustic data storage tag intended for the tracking of small fish. The essential components of the system have been integrated in standard 0.5um CMOS technology. Geopositioning of the tag is achieved by measuring the transit time of a sonar signal emitted from a fixed source location. The received sonar signal is pre-amplified, filtered by three switched-capacitor filters, digitized, and then correlated with the expected pattern stored in internal memory. The monolithic temperature sensor is embedded in a band-gap reference circuit. The analog output of the temperature sensor is converted to digital by means of a 10 bit switched-capacitor ADC. The external memory stores all physical data such as sound arrival time, water temperature, and pressure. A power-on-reset and a battery check circuit are utilized for power management.; Each analog CMOS circuit block has been successfully designed, fabricated, and tested. Testing has proven that every analog unit meets the required specification. |
