Abstract
This paper describes the performance of an improved transcutaneous optical coupler system. In this newly-designed system, an infrared LED and a set of phototransisters are placed face to face with the skin between them. Informations from a simulated artificial heart system are converted into an optical signal by the LED, transmitted through the skin, and detected by the phototransistors that are arranged in the shape of a circle. The informations are transmitted in the form of a digital signal in the infrared region because, in this way, power is effectively saved and high reliability in view of electromagnetic compatibility can be assured. With several phototran-sistors arranged in a set, and with a wave-shaping circuit added on the receiving side, the new system can allow for greater misalignment of LED and phototransistors that may possibly be caused by the movement of the patient. For a misalignment of 12mm, a signal transmission rate of 19200bps was attained with the new system, which is 8 times greater than what is possible with the conventional system. Attainment of this signal transmission rate was also confirmed by an in vivo experiment carried out with a grown goat.