Linear Non Iterative Sinusoidal Fitting Algorithm for Microbial Impedance Biosensor

Sine wave signals are widely used in electronic applications such as digital oscilloscopes calibration, speech analysis and electrochemical sensors. In particular, impedance based microbial biosensors detect bacterial concentration by stimulating the sample with a sinusoidal test signal and measuring its electrical characteristics. Thus, for reliable microbial biosensing, fast and accurate sine wave analysis is mandatory. Many algorithms for the estimation of sinusoidal parameters exist that provide accurate estimate but are based on time consuming iterative procedures and/or need good starting values for the sine parameters. In this paper a linear non iterative algorithm based on the least squares method is presented that allows sinusoidal voltages analysis in a fast and efficient manner. The algorithm has been tested either with simulation analysis either with real impedances and the results proved to be accurate enough for reliable bacterial concentration measurement.