Uncertainty Analysis of Impedance Measurements Using DSP Implemented Ellipse Fitting Algorithms

Impedance measurements are extremely important in many fields of science and accurate impedance measuring devices are therefore required. Besides accuracy, low-cost and portability are also sought after characteristics in some applications. A DSP based prototype has been developed to accurately measure impedances. An ellipse fitting algorithm is implemented in this device introducing many advantages in terms of speed and memory requirements, when compared to other signal processing algorithms commonly used, such as sine-fitting. In this paper, the developed prototype is used to measure an RLC series impedance in a range of frequencies and the experimental measurement uncertainty is analyzed.