Molecular Electronic Angular Motion Transducer Broad Band Self-Noise

Abstract

Modern molecular electronic transfer (MET) angular motion sensors combine high technical characteristics with low cost. Self-noise is one of the key characteristics which determine applications for MET sensors. However, until the present there has not been a model describing the sensor noise in the complete operating frequency range. The present work reports the results of an experimental study of the self-noise level of such sensors in the frequency range of 0.01–200 Hz. Based on the experimental data, a theoretical model is developed. According to the model, self-noise is conditioned by thermal hydrodynamic fluctuations of the operating fluid flow in the frequency range of 0.01–2 Hz. At the frequency range of 2–100 Hz, the noise power spectral density has a specific inversely proportional dependence of the power spectral density on the frequency that could be attributed to convective processes. In the high frequency range of 100–200 Hz, the noise is conditioned by the voltage noise of the electronics module input stage operational amplifiers and is heavily reliant to the sensor electrical impedance. The presented results allow a deeper understanding of the molecular electronic sensor noise nature to suggest the ways to reduce it.

Frequency response and self-noise of the MET hydrophone

“…This noise is generated from hydrodynamic fluctuation of the electrolyte through the electrochemical MET cell. From Safonov (2003) and Zaitsev et al (2015) we know that there is another noise type connected to arising of the close vortex in the channel. This noise is called geometrical and is given by the formula…”

“…where α is the dimensionless empirical coefficient, which characterizes scatter of the transfer function for different micro-channels of the electrochemical MET cell. Numerical value α = 0.31 is calculated in Zaitsev (2015). Moreover, there is noise described in Safonov (2003) that is generated from convection.…”

“…The coefficient K (ω, s el ) characterizes convection. The numerical value of K (ω, s el ) for s el = 15.7 mm 2 and the electrodes' channel 6 × 6 mm has been calculated in Safonov (2003) and Zaitsev (2015).…”

“…The model of its self-noise is built based on the previous knowledge of the physical processes responsible for noise in the MET sensor systems (Kozlov and Safonov, 2003). Including such physical mechanisms as convective noise (Safonov, 2003), noise caused by the impedance of the transforming element (Shabalina, 2007), hydrodynamic noise and noise due to the geometry of the electronic node (Zaitsev et al, 2015), and noise due to cross axis sensitivity (Zaitsev et al, 2018a) has been considered.…”

Study of Systems Error Compensation Methods Based on Molecular-Electronic Transducers of Motion Parameters

“…where Ω is the projection of the Earth angular velocity on the rotation plane of the molecular-electronic sensor sensitivity axis, δ is the phase of the output useful signal, ω is the average speed of the platform rotation, U gsens is the parasitic sensor signal, caused by the rotation axis beating, which contribute Journal of Sensors into the system signal due to the sensitivity to linear acceleration and the corresponding changes in the gravity vector projection on the sensitivity axis of the device, U enc is the encoder signal measuring the platform rotational speed over time, α is the deviation angle of the molecular-electronic sensor sensitivity axis from the perpendicular to the platform angular velocity vector (the angle of nonorthogonality), and U noise is the self-noise of an angular sensor, considered in detail in [19,20].…”