Microminiature radiotelemetrically operated sensors for small animal research

摘要

An instrumentation system for monitoring various physiological functions in small animals utilizes injectable electronic devices. These implanted devices receive power and control data from an RF carrier signal by inductive coupling. The RF carrier is generated by an external control unit with a coil that surrounds the animals and simultaneously energizes one or more implanted devices. Digitally encoded commands can be addressed to each uniquely addressed implant. These commands permit the implant to select among analog signals from various sensors and to adjust the gain of amplification before digitizing these signals. These commands instruct each implant in turn to generate a back-telemetry signal during pauses in the externally generated RF carrier. The back-telemetry signal is an amplitude-modulated RF signal that encodes the digitized data from the selected sensor. The back-telemetry signal is detected by the external coil and control unit. An algorithm in the external control unit computes the optimal gain for each sensing function in each implant. This instrumentation system permits large numbers of animals to be monitored more or less continuously with minimal human intervention and without requiring attached wires or harnesses that might interfere with their physiological functions