Impedance measurement front-end based on signal four-phase detection
Journal Title: Вісник НТУУ КПІ. Серія Радіотехніка, Радіоапаратобудування - Year 2018, Vol 0, Issue 72
Abstract
Internet of Things (IoT), a new direction in information and communication systems, has a significant impact on the development of novel electronics devices. Further progress in the field of IoT devices is conditioned by the development of sensor devices, and in particular, analog front-ends and signal converters for IoT sensors. High sensitivity and wide range applications of IoT sensors can be achieved by methods of impedance spectroscopy. Compared with other methods of physical research, impedance spectroscopy and based on it IoT sensor devices provide ease of implementation, high energy efficiency, good resolution and selectivity. In this paper, we present results of the development and model study of the impedance measuring transducer using the four-phase signal integration method. The implementation of impedance spectroscopy assumes a transition from frequency plots to plots on the complex plane, called as Nyquist plots. The data obtained in this paper are based on the SPICE (Simulation Program with Integrated Circuit Emphasis) model studding methodology, which compares small signal Alternative Current Analysis with large signal Transient Analysis. During the Alternative Current Analysis, Nyquist impedance plot are obtained in the idealized case, and during the Transient Analysis the active ReZ value and reactive ImZ impedance components are calculated for the actual parameters of the measuring transducers and the form of the activating signals. We have proposed a new solution of the impedance measuring transducer based on the four-phase signal commutation and integration method. This method consists in the formation of four informative signals, namely, the voltages $V_{Q1}$, $V_{Q2}$, $V_{Q3}$ та $V_{Q4}$, each of which corresponds to the integration results in the corresponding four phases of the activation signal. In these phases, or time t, the sign functions $A_{Q1}(t)$, $A_{Q2}(t)$, $A_{Q3}(t)$, $A_{Q4}(t)$ of synchronous detections are used: $A_{Q1}(t)=1$ at $t=[0...\pi/2]$; $A_{Q2}(t)=1$ at $t=[\pi/2...\pi]$; $A_{Q3}(t)=1$ at $t=[\pi...3\pi/2]$; $A_{Q4}(t)=1$ at $t=[3\pi/2...2\pi]$. In other time these sign functions are equal 0. Output signals of the impedance measuring transducer, namely, voltages of active $V_{RE}$ and the reactive $V_{IM}$ components are formed by adding and subtracting the numerical values of the above four voltages: $V_{RE}=V_{Q1}+V_{Q2}-V_{Q3}-V_{Q4}$; $V_{IM}=V_{Q1}-V_{Q2}-V_{Q3}+V_{Q4}$. The main units of the impedance measuring analog front-end are a synchronous quadrature detector and an integrator or filter. In comparison to traditional two-phase detection, four-phase detection we have proposed allows avoiding intermediate signal transducing, which provides a significant simplification of impedance measuring transducing. This simplification is achieved by directly integrating the instantaneous value of the $I_{Z}(t)$ current. Important dependences of the measuring transducer output voltages with four-phase integration on the operational amplifiers bandwidth are obtained. Results presented in the article are important for developing a new generation of microelectronic IoT sensor devices based on impedance spectroscopy methods. Main areas of application of such sensor devices are materials science, biochemistry, instrumentation, avionics, ecology, etc.
Authors and Affiliations
G. Barylo, R. Holyaka, I. Prudyus, S. Fabirovskyy
Keywords
Related Articles
- EP ID EP308176
- DOI 10.20535/RADAP.2018.72.62-68
- Views 124
- Downloads 0
Two-step method of the measurement data processing of the high-sensitivity radiometric system
Introduction. The radiometry systems for registration low-intensity noise signals are widely used in science and technique. Automation of such apparatus allows to improve the precision of measurements and facilitate inte...
Investigation of the resonance absorption of bioobjects mm-radiations
The results of investigation of absorbing capacity of cereals, water and human skin in mm-wave band are presented.
The mathematic model of the building and analyze make use of the converter voltage
This article presents methodize and analyze of the results for the connection source energy with execution devices through the operation transmitter.
Miniature devices based on electromagnetic crystals
Introduction. Crystal-like structures with specific spectral characteristics are widely investigated for signal processing devices. Brief review of electromagnetic crystals (EC) and EC-inhomogeneities is presented. Minia...
Modern devices of optimum filtration for the active radar system
The principle of construction the matched filter and correlator, for the active radar system operating with a broadband noise signal is esteemed. The example of construction a сhan-nel of processing on the basis of micro...