PRELIMINARY TESTING OF FLEXIBLE ELECTRODES FOR BIOSIGNAL MEASUREMENT: ABRASION RESISTANCE

With growing interest in monitoring the health status of a human has raised demands on measuring systems and devices. It is important to develop monitoring system with user friendly and comfortable interface. This applies not only to setup and control but also to wearing and manipulation. Therefore, the replacement of conventional metal, rubber and selfadhesive electrodes by electrodes with thin-film conductive layer is desirable. These electrodes combine good electrical properties altogether with comfortable wearability, ease of manipulation and low-cost fabrication. The indicated factors allow these electrodes to be used in commercial measuring systems and devices. Their applicability in long term measurements is subject to meeting additional requirements, such as chemical and mechanical resistance. Abrasion caused by rubbing the human skin during standard measurements might affect the functionality of the electrode. Four types of electrodes based on Au, ITO, Graphite filled polymer and PEDOT:PSS underwent series of testing of their abrasion resistance. A surface with specific roughness and pressure force was used. A change in amplitude of testing ECG signal was measured as a function of number of abrasion cycles for all electrodes

IMPLEMENTATION OF PULSE OXIMETRY MEASUREMENT TO WIRELESS BIOSIGNALS PROBE

Monitoring of heart rate variability (HRV) and oxygen saturation is important in medicine as well as training of top athletes. Our work describes the implementation of pulse oximetry functions in sensor system for measurement of biosignals. It allows us to follow along even pulse biosignal and the flow rate of blood

MONITORING OF EMG TO FORCE RATIO USING NEW DESIGNED PRECISE WIRELESS SENSOR SYSTEM

This work is focused on problematic of biopotential signals measurements (EXG) using powerful SMART sensor system, composed of portable units, intended for in-time wireless measurement and evaluation of electrical activity, produced by skeletal muscles, human heart or brain. Here, we discuss very precise measurement features, which characterize this device (high gain, low noise, wireless data transfer, multi-probe measuring), some special features as low voltage and ultra-low power consumption were reached by application of the described amplifier in order to achieve its longer performance for daily use. It brings a lot of advantages to biomedical electronics and medical care. In order to optimize the performance of novel proposed smart biomedical instrument in our experimental part we have focused on measurement of surface electromyography (sEMG) signal to force ratio. These sEMG signals can illuminate our understanding of how the brain controls muscles to generate force and produce movement and can be used in such applications like as training of athletes, controlling robots, monitoring the physical capabilities of patients with motor disorders etc

Development of a Device for On-Die Double-Pulse Testing and Measurement of Dynamic On-Resistance of GaN HEMTs

On-die testing can accelerate development of semiconductor devices, but poses certain challenges related to high frequency and high current switching. This paper describes design and development of a tester for double-pulse switching test and measurement of dynamic on-state resistance of unpackaged High-Electron-Mobility Transistors (GaN HEMTs). The tester is capable of switching an inductive load at drain-to-source voltage up to 400 V and drain current up to 10 A. Design challenges resulting from specific properties of GaN HEMTs and on-die measurement are explained, and solutions are proposed. Essential parts of the developed device are described, including low inductance gate-driver and measurement methods. Modified drain voltage clamping circuit for accurate on-state drain voltage measurement is described. The tester is constructed as a printed circuit board, integrated into a probe station. Voltage and current waveforms are measured with oscilloscope and used to calculate the on-resistance. Results of a reference measurement with commercially available packaged transistors are presented. Waveforms measured on experimental unpackaged normally-off GaN HEMT samples are also presented and discussed. The proposed tester device proved to be capable of performing the dynamic on-resistance measurement with satisfactory results