Development of a stair-step multifrequency synchronized excitation signal for fast bioimpedance spectroscopy.
Wideband excitation signal with finite prominent harmonic components is desirable for fast bioimpedance spectroscopy (BIS) measurements. This work introduces a simple method to synthesize and realize a type of periodical stair-step multifrequency synchronized (MFS) signal. The Fourier series analysis shows that the p-order MFS signal f(p, t) has constant 81.06% energy distributed equally on its p 2(n)th primary harmonics. The synthesis principle is described firstly and then two examples of the 4-order and 5-order MFS signals, f(4, t) and f(5, t), are synthesized. The method to implement the MFS waveform based on a field-programmable gate array (FPGA) and a digital to analog converter (DAC) is also presented. Both the number and the frequencies of the expected primary harmonics can be adjusted as needed. An impedance measurement experiment on a RC three-element equivalent model is performed, and results show acceptable precision, which validates the feasibility of the MFS excitation.
Department of Precision and Instrumentation Engineering, Xi'an University of Technology, Xi'an 710048, China.
Yuxiang
0000-0002-1837-3628
Y
Yang
Department of Precision and Instrumentation Engineering, Xi'an University of Technology, Xi'an 710048, China.
He
H
Bian
Department of Precision and Instrumentation Engineering, Xi'an University of Technology, Xi'an 710048, China.
Fangling
F
Du
Department of Electronic Engineering, Xi'an University of Technology, Xi'an 710048, China.
Qiang
Q
Sun
Department of Instrumentation Science and Technology, Hunan University, Changsha 410082, China.
He
0000-0001-8024-1899
H
Wen
D017097:Electric Impedance; D005583:Fourier Analysis; D012815:Signal Processing, Computer-Assisted; D013057:Spectrum Analysis