Performance of an Adaptive Current Source for EIT Driving Loads through a Shielded Coaxial Cable.

Area of Science:

• Electrical Engineering
• Biomedical Instrumentation
• Signal Processing

Background:

• Coaxial cables in Electrical Impedance Tomography (EIT) significantly impact system performance due to shunt capacitance.
• Existing solutions like driving cable shields or using active electrodes present challenges such as complexity, stability issues, packaging, and hygiene concerns.
• There is a need for simpler, robust methods to mitigate signal degradation caused by coaxial cables in EIT systems.

Purpose of the Study:

• To introduce and evaluate a novel high-precision current source designed for EIT applications.
• To assess the performance of this current source when driving loads through coaxial cables.
• To demonstrate the source's capability to compensate for current lost in shunt impedances, including cable losses.

Main Methods:

• Development of a new high-precision current source with adaptive output.
• Experimental setup to test the current source driving various loads (resistive and complex).
• Comparison of performance using three coaxial cable configurations: no cable, driven-shield RG-174 cable, and grounded-shield RG-174 cable (up to 1 MHz).

Main Results:

• The novel current source successfully compensates for current lost due to shunt impedance.
• Experimental results up to 1 MHz show similar performance across all tested cable configurations.
• The source demonstrates satisfactory performance even when using a standard grounded-shield coaxial cable.

Conclusions:

• The developed high-precision current source effectively mitigates the detrimental effects of coaxial cable shunt losses in EIT.
• This technology simplifies EIT system implementation by enabling the use of conventional grounded-shield cables.
• The findings suggest a more practical and potentially cost-effective approach to EIT instrumentation.