A 10 MHz Read-Out Chain for Electrical Impedance Tomography

Abstract

This paper presents the design and implementation of a read-out chain for electrical impedance tomography (EIT) imaging. The EIT imaging approach can be incorporated to take spectral images of the tissue under study, offering an affordable, portable device for home health monitoring. A fast read-out channel covering a wide range of frequencies is a must for such applications. The proposed read-out channel comprising a programmable gain instrumentation amplifier, an analog-to-digital converter (ADC), and an ADC driver is designed and fabricated in a 0.18 m CMOS technology. The proposed read-out chain operates over the wide frequency range of 100 Hz to 10 MHz, with an average signal-to-noise ratio of more than 60 dB. The entire read-out channel consumes between 6.9 and 21.8 mW, depending on its frequency of operation.

Impedance Spectroscopy Based on Linear System Identification

“…1a, should not exceed a second-order IIR filter transfer function up to f CLK /2, otherwise the algorithm's estimation fit deteriorates. To mitigate this issue, the SUT can be placed in an open-loop configuration using a differential currentsteering DAC [15], [16] and a wide-band instrumentation amplifier [9], [25]. In this way, the stability issue can be avoided.…”

A 122 fps, 1 MHz Bandwidth Multi-Frequency Wearable EIT Belt Featuring Novel Active Electrode Architecture for Neonatal Thorax Vital Sign Monitoring

“…performance voltage acquisition front-ends for bioimpedance measurements have been reported [23], [24] but mainly for onechannel recording. Read-out chains for EIT that use current feedback IA for wideband, high CMRR have been also reported [25], [26]. However, (see Fig.…”

Electrical Impedance Tomography for Biomedical Applications: Circuits and Systems Review

“…The working principle of CFIA can be found in [89] and the CMRR analysis for CFIA is detailed in [86]. Variations of this design could be CMRR enhancement feedback loop [19], and a wide bandwidth (10 MHz) design [9]. The gain of both the CFIA and RFIA can be set using resistance ratios.…”

“…is the total number of frames measured for the calculation, ) is the measured channel voltage and ) w is the average voltage measured within channel over N frames. Such SNR ab rrrrrrrrr represents the system measurement repeatability and is commonly used in many systems reported in the literature [9], [20], [88], [92], [93].…”