Development of Metrological Maintenance of Photometric Devices For Pulsometry

Abstract

Investigating pulse in different parts of the body is of great interest to doctors. The purpose is the development of metrological maintenance, calibration and certification of photometric instruments [1—3]. Photoplethysmograph is designed to record changes in optical density of a person’s body area with a beam of light reflected in the light [4—6]. Measurements are carried out non-invasively [7]. Such device registers pulse wave (PW) signals and reference ECG with computer processing, Fig. 1—2 [8—10]. A working measure (LED) was created and calibrated using an optical radiation power meter based on the substitution method [11], test bench is at Fig. 3, calibration results — in Table 1 and Fig. 4. Test bench for device calibration and an optical radiator are at Fig. 5—6, view of calibrated signal — at Fig. 7. As a result of calibration (Table 2) the dependence of the output signal on LED power supply (Fig. 8) is obtained, and the calibration dependence is shown at Fig. 9. In the test bench for SMC used standardized light filters KNS-01 at a wavelength of 630 nm (Fig. 10a). The calibration curve is calculated as the dependence of the relative coefficient of inverse light dispersion (RCILD) on PW (Fig. 10b, Table 3). The view of output signal is at Fig. 11. As a result of SMC, the limits of permissible absolute error of 2 % in the range of RCILD (15—100) % are defined.