Abstract: A method of compensating periodic error signals in sensor output is provided. The method comprises obtaining a sum signal from sensing outputs of M sensor elements (where M is a positive integer), obtaining the amplitude and phase of N frequency components included in the sum signal, and calculating a sensing output gain adjustment coefficient for each sensor output. To ensure that a sum signal level obtained by summing a pre-adjustment output of each sensor element multiplied by the gain adjustment coefficient equals a sum signal level obtained by summing the unmodified outputs of the sensors, a gain adjustment coefficient is obtained for each sensor output by using a calculated scaling coefficient to perform pre-adjustment scaling of each gain adjustment coefficient. The adjustment gains thus obtained are used to adjust the gain of each sensor output.