Electronic and Electromechanical Tester for physiological sensors
Historically, physiological sensors used for measuring respiratory, cardiovascular and electrodermal activity have been used with polygraph devices and sleep laboratories. Periodic testing of these sensors is imperative to maintain sound performance of the measurement device. This thesis presents an Electronic and Electromechanical Tester (EET) for physiological sensors used with polygraph instruments that can accurately and repeatedly reproduce both physiological signals originating from the human body as well as computer-generated signals. The tester is interfaced to a personal computer via USB and contains the following four time-synchronous channels: two electromechanical simulators for testing abdominal and thoracic respiratory sensors, an electromechanical simulator for testing a sphygmomanometer used to capture cardiovascular activity, and an electronic simulator for testing electrodermal sensors. All of the simulated physiological channels apply direct physical actuation to the corresponding sensors. Specifics of software architecture and hardware implementation are included along with validation examples and test results. System identification techniques are discussed and transfer function models are defined. Based on these transfer function models, a compensator is designed with a goal of improving validation test data. The EET demonstrated its ability to reproduce physiological signals with adequate accuracy and repeatability. Finally, future systematic improvements as well as additional application areas are explored.