Recent Advances in Crest Factor Minimization of Multisine

Multisine signals are used in many applications like fast estimation of frequency response function, as well as in a variety of other fields. Synthesis of a low crest factor (CF) multisine waveform with the given amplitude spectrum depends on initial phases of its components. Approaches for finding good initial phases can be divided into two classes: analytical, direct formula calculations and use of numerical iterative search algorithms. In some cases, the direct formula calculation is used as a starting point for the further iterative search. This paper presents both, new direct formulas and an improved iterative search algorithm to synthesize arbitrary spectrum multisine with the lowest CF. Comparison with the results of earlier methods proves the positive effect of proposed modifications

Multichannel Electrical Impedance Spectroscopy Analyzer with Microfluidic Sensors

Impedance spectroscopy is a common approach in assessing passive electrical properties of biological matter. However, several problems appear in microfluidic devices in connection with the requirement for high sensitivity of signal acquisition from small volume sensors. The developed compact and inexpensive analyzer provides impedance spectroscopy measurement from three sensors, both connected in direct and differential modes. Measurement deficiencies are reduced with a novel design of sensors, measurement method, optimized electronics, signal processing, and mechanical design of the analyzer. Proposed solutions are targeted to the creation of reliable point-of-care (POC) diagnostic and monitoring appliances, including lab-on-a-chip type devices in the next steps of development. The test results show the good working ability of the developed analyzer; however, also limitations and problems that require attention and further improvement are appointed