Journal of the Faculty of Engineering and Architecture of Gazi University, cilt.39, sa.3, ss.1797-1813, 2024 (SCI-Expanded)
The general expression of the system design to transfer the simulated biosignals via a computer based simulator program to the physical environment via an emulator circuit is shown in Figure A. The system can be broadly divided into two subsystems. The first subsystem is a computer based simulator program that can generate and simulate biosignals. The second subsystem is an emulator circuit that converts the generated digital biosignals to analog biosignals. Purpose: Providing a single reconfigurable hybrid circuit topology in the level of Volts and mV for synthetic biosignal generation, test signals generation, HMI applications and medical devices; eliminating the limitation of biosignal databases by bringing flexibility to simulate, generate and record biosignals thanks to adjustable signal characteristics can be listed as purposes of the study. Theory and Methods: ECG, EEG and EMG biosignals have different amplitude ranges and different frequency components. So that almost completely different filter structures, electronic elements and circuit designs are required to produce the aforementioned biosignals separately. The idea of collecting the different designs required for each biosignal generation on a single electronic card will increase the card sizes, increase the costs, will not be innovative, flexible and usable. So that it is a necessity to focus on the concept of "reconfigurability". In order to provide these features, a configurable Field Programmable Analog Array (FPAA) based hybrid system design that can be controlled with a computer based simulator has been propoesed and developed in this study to generate synthetic biosignals. In addition, an opportunity is given to users in order to create their own biosignal databases by adjusting the sampling frequency and other signal characteristic with the computer based biosignal simulator developed within the scope of the study. Results: Simulated biosignals were examined on excel spreadsheet. Generated biosignals were observed on outputs of FPAA based emulator by picoscope. According to simulation results and experimental results, biosignal realization tables with error rates were created to express the signal accuracy. The results show that switched capacitor FPAAs have great potential to generate analog biosignals. Conclusion: The existence of a biosignal emulator is important because the signals produced by each human body are not exactly the same due to psychological and physical effects. Existence of a biosignal emulator allows innovations and developments in various fields such as control applications and artificial intelligence algorithms. It is predicted that studies about biosignal emulators will give a new direction to the literature.