Electrical impedance spectroscopy is a powerful technique which can be used to characterize properties of many materials, including biological tissues. In medical applications, it is typically used as a complementary tool for diagnostic, helping improve the ability of current techniques to distinguish pathological tissue from normal tissue. Commercially available equipment to perform impedance measurements is usually expensive and impractical, lacking the necessary flexibility and compactness to use it as a fast prototype tool for research. The high cost and the difficulty in transporting it make it unsuitable for early-stage investigation in real-world clinical settings. Consequently, researchers at the Electronic and Biomedical Instrumentation Group at the Universitat Politècnica de Catalunya have been working on low-cost alternatives, which try to solve the aforementioned issues. The system described in this work aims to be such an alternative, being based on a low-cost electronic board capable of performing fast signal generation and data acquisition. In particular, its main focus is on fast measurements using multisine signals, with the one employed in this work consisting of 26 frequency components from 1 kHz to 1 MHz. The system has been designed with flexibility in mind, allowing the user to have complete control over the generation and acquisition chains thanks to its highly modular architecture, making it particularly well-suited for research purposes. The objective of this document is to give a thorough overview of the design and implementation of this system, focusing on the main architectural ideas but also covering many of the finer details. Some measurements, performed at a rate of approximately 950 spectrums per second, are briefly discussed at the end, and they serve both as validation of the implemented design and as an outline for future research directions.
