Design and Self-Noise of MET Closed-Loop Seismic Accelerometers

Molecular electronic transfer (MET) technology offers an alternative approach for the development of accelerometers with high dynamic range and low self-noise. The best performance is achieved by using a force-balancing feedback. However, the operating principles of the feedback sensors has not been reporting yet, also, there is not any comprehensive theoretical model describing sensor noise in the complete operating frequency range. This paper reports on the development of the feedback system for an MET seismic accelerometer, a feedback stability analysis, and an optimization of the signal conditioning feedback electronics to get the highest dynamic range. Also, both the theoretical model and experimental results of such sensors self-noise are presented in the range of 0.1-120 Hz. According to the model and the experimental observation, there are two major contributors into self-noise: convective processes in the electrolyte and electronic noise of the signal operational amplifiers. The research results give better understanding of the molecular electronic accelerometers noise nature and suggest ways to reduce it.