Optimization of infrared biotelemetry systems

An infrared telemetry system is analysed, particularly on the receiver side. How an array of photodiodes and choice of optimal load resistance can improve the photoreceiver sensitivity in current and photovoltaic mode is shown. In photovoltaic mode also a parallel load resistor to each diode is necessary to obtain highest photo voltage. Pulse modulation with low duty-cycle is optimal in case when transmitter has to save energy because is carried by the patient. The limit in number of channels and channel bandwidth related to pulse width is discussed. Also an advantage of simple relay unit is described.