Novel Method for Recording High Frequency Human Skin Temperature Oscillations

Abstract

Circuitry solution has been developed to create a prototype of the system for the registration of the high frequency human skin temperature oscillations. As they connected with blood circulation, such method allowing in the future to provide the registration of the pulse wave signal, for measuring heart rate in portable devices like smart watches and fitness bracelets. The miniature semiconductor chip diodes sensor has been used. The electronic system for the calibration of the device has been designed. For providing operation of the system in a full voltage range using the automatic set has been used for the maintenance of the operating point and of the necessary slope of the conversion factor (Volts / °C). The structural and circuit diagram has been developed. They consisted of two parts: the remoted preamplifier with the temperature sensor and the main block including all the other digital and analog parts. The developed system has following technical characteristics: the temperature resolution to be 0.01 °C and the thermal time constant of the sensor 0.05 s. The registration system testing has been performed in two ways: in a thermostat and on the human skin surface. Device contains plethysmo- and ECG-channels for obtaining data on the phases of cardiac cycles and synchronous analysis of physiological processes. The cross correlation coefficient between the temperature oscillations and the pulse wave signals laid in the diapason from 0.53 to 0.65.

Keywords

• fast high-sensitivity thermometry
• medical thermometer
• temperature oscillations
• pulse waves