AJP - Heart and Circulatory Physiology, Vol 244, Issue 1 162-H165, Copyright © 1983 by American Physiological Society
Crystal-controlled telemetry system for long-term acquisition of physiological data
R. M. Anderson, A. Livnat and J. E. Zehr
A crystal-controlled telemetry system was developed for long-term
high-reliability recording of blood pressure in unrestrained animals. The
miniaturized transducer-transmitter system is powered by two lithium
batteries that allow for more than 200 h of continuous recording of blood
pressure before battery replacement. The total system has a flat frequency
response of 0-25 Hz and a time stability of +/- 1 mmHg/day. Linearity is
better than 0.5%. The high degree of dependability of the system permits us
to perform continuous, unattended, around-the-clock recordings of pressure
and heart rate in unrestrained animals. Very high dependability is achieved
by the use of a novel piezoresistive blood pressure transducer and by the
inherent stability of the crystal-controlled radio-frequency oscillator of
the transmitter. The receiver is also crystal tuned to the measured
transmitter frequency. This transmitter-receiver frequency locking ensures
very reliable reception of the telemetered signal.
