Optimal requirements of a data acquisition system for a quadrupolar probe used in resistivity and permittivity surveys

Abstract

This report discusses the development and engineering of a suitable quadrupolar probe for simultaneous and noninvasive surveys of electrical resistivity and dielectric permittivity. The quadrupolar probe can perform measurements on a subsurface with inaccuracies below a fixed limit (10%) in a bandwidth of low frequency (100 kHz). The quadrupole should be connected to an appropriate analog–digital converter that samples in phase and quadrature (IQ) or in uniform mode. If the probe is characterized by a galvanic contact with the surface, the inaccuracies in the measurements of resistivity and permittivity due to the IQ or uniform sampling analog–digital converter are analytically expressed. A large number of numerical simulations show that the performances of the probe depend on the selected sampler, and that the IQ is better compared to the uniform mode under the same operating conditions, i.e. for bit resolution and medium.

Keywords

• Instrumentation and techniques of general interest, Magnetic and electrical methods, Mathematical geophysics, Data processing.