4-subject 4-channel optical telemetry system for use in electrocardiograms

The implementation of a 4-subject, 4-channel optical telemetry system for the measurement of electrocardiograms (ECGs) is described in this paper, a system which receives and transmits physiological signals to the external system using LED and infrared light of photodiode. This system decreases the dependency of power supply voltage to the CMOS IC chip and also uses a new enforced synchronization technique using infrared bi-directional communication. The telemeter IC with the size of 5.1×5.1 mm² has the following functions: receiving of command signal, initialization of internal state of all functional blocks, decoding of subject selection signal, time division multiplexing of 4-channel modulated physiological signals, transmission of modulated signals to external system, and auto power down control. ECG is tested to confirm telemetry system