Binary signals in impedance spectroscopy

Abstract

Using of binary waveforms in the fast impedance spectroscopy of biological objects is discussed in the paper. There is shown that the energy of binary waveforms can be concentrated onto selected separate frequencies. We can optimize the binary excitation waveform depending on the shape of frequency response of the impedance under study to maximize the levels of signal components with certain selected frequencies. As a result, we are able to receive maximal amount of information about the properties and behavior of the impedance to be studied. We have designed and prototyped the impedance spectroscopy device operating in the frequency range from 100 mHz to 500 kHz to cover α- and β-regions of the bio-impedance spectrum of time-varying subjects as, for example, fast moving cells in micro-fluidic devices, beating heart and breathing lungs or the whole cardiovascular system.

Online Dielectric Response Analysis Under Mixed-Frequency Medium-Voltage Stress

“…While in this study only rectangular waveforms with a fixed frequency (1 kHz) and duty cycle (50%) have been used, it is possible to synthesize and apply pulse-width-modulated binary signals with tailored frequency spectra [9]. The voltage excitation would then be switched (e.g.…”

Development of a Stair-Step Multifrequency Synchronized Excitation Signal for Fast Bioimpedance Spectroscopy

“…More often only measuring several to tens of distinct frequencies (usually with large frequency intervals) is satisfactory. Therefore, the spectral sparse signals whose energy concentrates on the expected limited spectral lines, such as the sparse spectrum sequence (SSS) [ 27 ], the authors' MFM signals [ 22 ], and the MFS signals proposed in this paper, are more reasonable. According to the literature [ 27 ], a sample of the SSS signal has 76.2% of the total signal energy distributed equally on its four harmonics (1, 3, 5, 7).…”

Design and Evaluation of an Electrical Bioimpedance Device Based on DIBS for Myography during Isotonic Exercises

“…For example, in Z ex1 , the peaks only reached a constant value on days 1, 8 and 12. Nevertheless, in Z ex4 , the peak value stabilized on days 1,6,8,10,11,12,15,16. Therefore, we can suppose that, when the curve reaches a constant value, this means that the muscle is exhausted.…”

“…However, the time necessary to secure a full spectrum might be too large for some applications [11]. In living beings, there are processes that occur quickly and the traditional EBIS could not monitor them [12]. The fast EBIS also avoids artifacts caused by an MUT involuntary movement, which may lead to changes in the contact interface (electrode-electrolyte) and cause errors during the measurement [13].…”