PSK MODULATION WAVE CARRIER RECOVERY CIRCUIT, ITS REPRODUCTION METHOD AND RECORDING MEDIUM RECORDING ITS CONTROL PROGRAM

PROBLEM TO BE SOLVED: To attain recovery control of a carrier at a high speed by conducting FFT processing only once in the PSK modulation wave carrier recovery method. SOLUTION: This method utilizes a characteristic of an output of a phase error detection circuit 11 in the carrier recovery circuit of a PSK modulation wave that a gradient of a frequency offset of the output is reverse in its increasing direction to its decreasing direction. A direction of deviation of the frequency offset is detected by detecting the gradient in parallel with a result of an FTT arithmetic processing section 12 that detects the offset. The signal amplitudes before and after the phase difference detection output are compared for each sampling period and an up-down counter 15 counts the number of transitions in the increasing direction and the decreasing direction. A sign of the count indicates the gradient of the phase difference output and depicts a deviation direction of the frequency offset. The objective offset including the sign of the carrier frequency is obtained by multiplying the sign by the frequency offset obtained by the FFT processing.