Practical Design of Flow Meter for Mechanical Ventilation Equipment

Abstract

This article presents the hardware development stage of a high-resolution and low-noise multi-channel bioamplifier, designed to acquire 8 channels of biopotential signals by human brain emitted. Basically it's an 8-lead electroencephalograph (EEG), but designed to pick up signals with wide bandwidth, compared to common EEGs. This bioamplifier is made with the purpose of acquire signals from specific brain sectors, for frequency patterns study higher than the ranges commonly analyzed in conventional electroencephalography. The obtained product consists of 8 identical circuits coupled to capture all the signals with respect to a central electrode. Each circuits consists of a differential amplifier with common mode voltage feedback circuits, which allow improve the noise rejection ratio. High efficiency AC coupling circuits are used to reduce baseline shift without signal altering. Each lead has gain of 10000, to obtain amplitude levels in the Volts order from the signals captured in micro-Volts order. Preliminary results show that the system operates efficiently within a range of 0.5 to 300 Hz, with amplitude measurement error levels less than 0.1%.