A microcontroller-based telemetry system for sympathetic nerve activity and ECG measurement.
A telemetry system employing a low power 8-bit microcontroller has been developed for chronic unanesthetized small animal studies. The two-channel system is designed for use with animals in shielded cages. Analog signals from implantable ECG and nerve electrodes are converted to an 8-bit serial digital format. This is accomplished by individual 8 bit A/D converters included in the microcontroller, which also has serial I/O port. The converted serial binary code is applied directly to an antenna wire. Therefore, the system does not need to employ a separate transmitter, such as in FM or infrared optical telemeters. The system is used in a shielded animal cage to reduce interference from external radio signals and 60 Hz power line fields. The code is received by a high input impedance amplifier in the cage and is then demodulated. The telemeter is powered by a small 3 V lithium battery, which provides 100 hours of continuous operation. The circuit is constructed on two 25 x 25 mm. printed circuit boards and encapsulated in epoxy, yielding a total volume of 6.25 cc. The weight is 15 g.
Harada
E
E
Dept. of Electronics Engineering, Hiroshima Institute of Technology, Hiroshima 731-51, Japan.
Yonezawa
Y
Y
Caldwell
W M
WM
Hahn
A W
AW
D000818:Animals; D002415:Cats; D004562:Electrocardiography; D004567:Electrodes, Implanted; D004867:Equipment Design; D007668:Kidney / Q000294:innervation; D008838:Microcomputers; D013564:Sympathetic Nervous System / Q000502:physiology*; D013686:Telemetry