Voltage and phase calibration for a quad-channel FPGA controlled EIT modular system

This paper describes a quad-channel Field Programmable Gate Array (FPGA) controlled Electrical Impedance Tomography (EIT) modular device and the calibration techniques used to characterize the system. Each module consists of four independently sampled analog channels and a single FPGA. The system is modular and the number of total channels is scalable to the individual intended application. Each module stores its own calibration coefficients for phase and voltage, enabling the user to acquire precise real and imaginary components of the impedance at various excitation frequencies.