Using the Thue-Morse Sequence to Cancel Low-Frequency Fluctuations

Measuring the sensitivity of a system (e.g. a sensor) is usually done by sequentially applying different input levels and measuring the difference of the output levels. Repeating this procedure several times significantly reduces the effect of slow fluctuations; however these can be removed completely by choosing an optimal sequence of input stimuli. We used the binary thue-morse sequence as a stimulating sequence, and compared the results with those of the standard alternating sequence. We considered perturbations modeled as noise and exponential decay functions. Immunity to perturbations increased dramatically, especially for the exponential decay function, merely by reordering the stimulation sequence.