Patent ID: 8355479

Claim:
A signal processing apparatus comprising: a sampling clock generation unit for generating a sampling clock by delaying, by a predetermined amount, a phase of a driving clock having the same frequency as a carrier wave; a logic data generation unit for generating a plurality of logic data in synchronization with the driving clock, wherein the plurality of logic data are generated by using the predetermined driving clock generated by the sampling clock generation unit to sample a modulation signal obtained by shifting a phase of the carrier wave; a sampling bit string generation unit for generating a sampling bit string having a length longer than one cycle of the carrier wave by shifting the logic data generated by the logic data generation unit in accordance with the predetermined driving clock; a phase error data generation unit for using a bit string corresponding to one cycle of the carrier wave extracted from the sampling bit string generated by the sampling bit string generation unit to generate phase error data representing an amount of shift between a phase of the bit string and the phase of the carrier wave, wherein the phase error data generation unit includes: a detected data calculation unit for calculating soft-decision data, serving as detected data, obtained by adding a predetermined first weight to each bit value in the bit string, a phase data calculation unit for calculating soft-decision data, serving as phase data, obtained by adding a predetermined second weight to each bit value in the bit string, wherein the predetermined second weight is different from the predetermined first weight, and a phase error data calculation unit for calculating the phase error data, based on the detected data calculated by the detected data calculation unit and the phase data calculated by the phase data calculation unit; and an extraction position determination unit for determining, based on the phase error data generated by the phase error data generation unit, an extraction position of the bit string, corresponding to the one cycle, having a phase similar that of the carrier wave.