A Multichannel Ultrasonic Marine Biotelemetry System for Monitoring Marine Animal Behavior at Sea.
CALIFORNIA STATE UNIV LONG BEACH DEPT OF BIOLOGY
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Up to eight multiplexed channels of shark behavioral data at sea are obtained with a 40-kHz acoustic transmitter with a range exceeding 5 km and a life of up to 1 week. Conservation of battery power is achieved with complementary metal-oxide semiconductor CMOS integrated circuits ICs and a pulse-interval data format of 10-ms pulses at intervals between 200 ms and 2 sec. A multivibrator oscillator is used to control the operating frequency, which is essentially independent of temperature and pressure and decreases slightly with battery voltage 800 Hz2-volt drop. An optional crystal oscillator maintains constant frequency. The pulse repetition rate is not significantly affected by voltage, pressure, and temperature. Fail-safe devices ensure operation in the event of sensor or multiplexer failure. Sensors are described for measuring depth, swimming speed, compass heading, ambient light, and temperature. Data are primarily reduced in the laboratory from field recordings computer reduction is under development. The transmitter is adaptable to other hydrospace or aerospace uses with acoustic, electromagnetic, or hard-wire media. Modified author abstract
- Biological Oceanography
- Biomedical Instrumentation and Bioengineering