Wide Frequency Impedance Meter Analysis
A I Levin, Ekaterina A. Pecherskaya, Oleg V. Karpanin, Vladimir V. Antipenko, Yuriy A. Varenik, Anastasia E. Shepeleva · 2022 IEEE 23rd International Conference of Young Professionals in Electron Devices and Materials (EDM) · 2022
The capabilities of the Analog Devices AD5933 impedance network analyzer microcircuit, which performs high-speed single-frequency continuous impedance measurements, are investigated in this paper. The AD5933 chip operation principle is based on the Discrete Fourier Transform, which is implemented using analog-to-digital conversions. Hardware and software features of working with this chip are demonstrated. As a result of testing the proposed impedance meter based on the AD5933, experimental results were obtained that are comparable with the results obtained by the MS5308 laboratory meter from Precision MASTECH Enterprises. The effect of AD5933 electrical impedance analyzer calibration methods on impedance measurement errors is considered. It is proposed to exclude the constant component of signal measurement when measuring the impedance of biological objects, which makes it possible to avoid the process of polarization at the “electrode-biological tissue” interface and in the structure of the tissue itself. This is achieved by introducing an additional cascade on an operational amplifier connected according to the follower circuit. The application of this microcircuit for measurements of bioimpedance for the purpose of application in plethysmography and rheography is considered. On the grounds of the test results, it was concluded that the impedance meter based on the AD5933 microcircuit allows obtaining reliable results with a measured impedance from 1 kΩ to 16 kΩ in the frequency range from 1 to 100 kHz. The deviation of the measurement results does not exceed ±2%.