Signal detection algorithms for interferometric sensors with harmonic phase modulation: miscalibration of modulation parameters

In the current paper, we have developed an analytical apparatus that allows us to calculate the phase error produced by miscalibration of modulation parameters. The case of harmonic modulation is considered, and the analysis is performed for cases of miscalibration for two parameters: amplitude and start phase. Two demodulation algorithms are considered: a conventional 4-point algorithm, based on an ordinary least-squares approach, and a previously developed 4+1 algorithm with high immunity to phase error, induced by change of target phase on the demodulation interval. Predictions, given by developed analytical equations, are verified by means of numeric modeling.