Design and analysis of pulse oximetry circuits

This section should be the shortest part of the abstract and should very briefly outline the following information: 1-What is already known about the subject, related to the paper in question. 2- What is not known about the subject and hence what the study intended to examine (or what the paper seeks to present). One of the devices that is widely used in medicine is PULSE OXIMETRY. This device, which is used in most ICU wards (cardiac intensive care unit) and operating rooms of hospitals in the country, is a device that can be used to determine the percentage of oxygen saturation in human blood. What is stated in this report is the study of the theory and design of a pulse oximetry system, which acts based on a red and infrared light, is transmitted through the connection of a transducer to the human body tissue and the detection of light passing through the other side of the tissue. In this report, in the first chapter, the introduction and in the second chapter, the principles of pulse oximetry system theory are examined. In this chapter, with the help of photon diffusion theory in finger tissue find the relationship between the ratio of DC changes in light intensity received by the detector to AC changes in light intensity in both red and infrared types with a variety of absorption and dispersion coefficients, and then with the help of it, we get the system calibration table and curve. In the third chapter, the design and principles of structure and familiarity with different classes of pulse oximetry system are discussed. And in the fourth chapter, we present the results of testing the device on different people, including heart patients, and reviewing the error of the device and suggestions for completing the system