Abstract
We have studied and developed a new type of the plethysmograph using a light emitting diode (LED) as a compact and radiant light source for the diagnoses of microcirculation system. The detected signal was put into a microcomputer and processed by various statistical analysis in order to evaluate the microcirculation diseases. We defined the risetime of output pulse Tu,the delay time Td between signal pulse measured on the foot and the ear, and -10dB and -20dB decay frequencies in the pulse spectrum f1 and f2, respectively. Thus these parameters were derived by using a microcomputer, and compared for normal and diseased human subjects. It was found that they can descrive successfully human microcirculation conditions necessary for the diagnoses.
