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

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.