Fast High-Impedance Spectroscopy Method Using Sinc Signal Excitation

Abstract

In this paper the method of fast impedance spectroscopy of technical objects with high impedance (|Z x | ≥ 1 GΩ) is evaluated by means of simulation and a practical experiment. The method is based on excitation of an object with a sinc signal and sampling the response signals proportional to current flowing through and voltage across the measured impedance. The object's impedance spectrum is obtained with the use of continuous Fourier transform on the basis of linear approximations between samples in two acquisition sections, connected with the duration of the sinc signal. The method is first evaluated in MATLAB by means of simulation. An influence of the sinc signal duration and the number of samples on impedance modulus and argument measurement errors is explored. The method is then practically verified in a constructed laboratory impedance spectroscopy measurement system. The obtained acceleration of impedance spectroscopy in the low frequency range (below 1 Hz) and the decrease of the number of acquired samples enable to recommend the worked out method for implementation in portable impedance analyzers destined for operation in the field.

Identification of characteristics of two-terminal networks from the pulse response of the current

“…(4) The performed studies of the preliminary approximation of the initial values of the response of the current and exciting pulses by 2nd to 7th order splines with variations of the data dimensionality, reachable accuracy of determining element values of the two terminal network, and the maximal frequency, dem onstrated this approximation efficiency. For example, for the calculation of value R to a frequency of 3 GHz with an accuracy of < 5% and with approximations by the 3rd order splines, the dimensionality of the initial data should be at least 165.…”

“…The study of two terminal networks is based on the current response to the pulse excitation. There are studies of this problem with different shapes of actuating signals [1,2,4]. For example, if the operational amplifier (Op amp) has a sufficient frequency band as compared with the measured two terminal network Z m , the equivalent circuit (Randles cell) shown in Fig.…”

Advanced Instrumentation for Polyharmonic Metal Detectors

“…Recently, sinc signal is widely used in many areas, for example in analogue to digital converters testing [46] or high-impedance spectroscopy [47] and it is very perspective signal thanks to its spectrum. Also the spectrum of the sinc signal is similar to the spectrum of the chirp signal.…”

Effect of ADC Resolution on Low-Frequency Electrical Time-Domain Impedance Spectroscopy

“…The transformation methods are generally based on Fourier [4], Laplace [11] or Wavelet [12] transforms. The excitation in the time domain spectroscopy is a wideband signal such as a multi-sinusoidal, chirp, Sinc signal [10], a pulse or white noise [12]. An advantage of using a wideband signal is that by applying a single excitation, the impedance spectrum of the entire desired frequency range can be obtained at once.…”

“…While applying a sinusoidal excitation signal to the tested sample is one of the most comprehensive and simplest methods for extraction of the impedance spectrum, it takes a long test time, especially at frequencies under 1 Hz [10]. Another issue of the method is its discrete frequency components: for each desired test frequency, at least one period of sinusoidal signal in that frequency should be applied to the sample.…”