Mixed-Signal Front-End Design for Concurrent Acquisition of Electrophysiological and Hemodynamic Brain Signals

Abstract

Abstract

Based on experimental evidence, multimodal neuro engineering applications in the case of electrophysiological monitoring and hemodynamic monitoring of a brain region demands simultaneous functionality, but is difficult because of the difference in signal amplitude, bandwidth and noise specifications that is very high indeed. Electrophysiological signals are microvolt-scale amplitude and bandwidth (KHz) signals, and hemodynamic signals are millivolt-scale amplitude and sub-10-Hz signals, so attempt to record both simultaneously is likely to be saturation artefact, crosstalk, and or timing error. The paper will discuss a mix signal front-end system that allows simultaneous capture of both modalities with a single and time synchronized signal chain. The proposed design uses dual analogue conditions along conditions along with modality selective gain and bandwidth isolation, and then an identical mixed-signal conversion stage, to synchronise sampling. To suppress inter-path interference and at the same time maintain sensitivity to low-amplitude electrophysiological signals a noise-optimised low-noise amplifier and frequency-selective filtering strategy is adopted. Noise in Analytical Noise Analytical noise models are developed to design circuits and choice parameters. Sub-microvolt input-referred noise Experimental validation of synthesised brain-signal emulation containable levels in combination with reliable concurrent acquisition of the electrophysiological path, low inter-modal crosstalk, and stable tracking of hemodynamic signals under simultaneous operation have been demonstrated. The findings affirm that, the proposed mixed-signal front-end offers scalable and low-energy efficient model of deployed multimodal brain-monitoring systems and facilitates compact and synchronised acquisitions architectures of next-generation neuro interface systems.