Patent ID: 7139333

Claim:
A receiver comprising: a sampling unit that sequentially samples a received signal modulated using a predetermined system; a plurality of demodulation processing units that have frequency correction values of mutually different sizes set in advance, and that correct frequencies of the sampled signals according to the frequency correction values, discretely demodulate the sampled signals after the frequency correction, output decision values and reliability information of the received signal, and detect each known synchronization word inserted into the received signal from the decision values; a decision value selecting unit that selects one final decision value from a plurality of decision values based on a plurality of pieces of reliability information and results of the detection of the synchronization words that have been output from the demodulation processing units; and a frequency error detecting unit that estimates a frequency error of the received signal based on a frequency correction value of the demodulation processing unit corresponding to the final decision value, wherein the demodulation processing unit carries out detection processing of a synchronization word corresponding to a decision value based on a plurality of known patterns obtained by phase-shifting a known synchronization pattern with a plurality of different phase shift quantities respectively, and specifies a phase shift quantity of a known pattern in which the synchronization word has been detected, and the frequency error detecting unit corrects the frequency correction value corresponding to the final decision value that has been selected by the decision value selecting unit, with the specified phase shift quantity, and estimates a frequency error of the received signal.