A multichannel physiological data/voice telemetry system

A seven channel physiological telemetry system was designed, constructed, and tested for a space environment to transfer physiological and voice information to and from an astronaut. Three ECG leads were monitored simultaneously, and two-way voice communication was achieved. The portable unit operated properly under ground based station (GBS) control. The major design problem was associated with the constraints of a wide bandwidth FM transmitter with crystal control combined with the tri-state logic format used. However, by using an ''indirect FM'' scheme and incorporating additional waveshaping circuits at the GBS, proper operation of the system was obtained. In the present form, the telemetry system has capability for seven channels of low level (2.5 mv peak maximum) physiological signals with bandwidths between 0.03 Hz and 100 Hz. Additional signal conditioning and modification of the instrumentation amplifier gains are required for other signals.