Patent ID: 8625230

Claim:
A position demodulator comprising: a demodulator configured to demodulate a first demodulated signal and a second demodulated signal having a phase difference of 90 degrees from the first demodulated signal, wherein the first and second demodulated signals are obtained as a result of a discrete Fourier transform operation on a read signal of a null servo pattern recorded in a servo area of a medium read out by a head; a phase corrector configured to carry out correction of the first demodulated signal and the second demodulated signal by tilting respective vectors of the first demodulated signal and the second demodulated signal by a predetermined angle, the vectors being represented on a phase plane using a sine component and a cosine component of each of the first demodulated signal and the second demodulated signal as values on coordinate axes that are different from each other; and a position demodulating module configured to demodulate a positional signal for determining a position of a core of the head based on the first demodulated signal and the second demodulated signal corrected by the phase corrector.