Patent ID: 7852728

Claim:
A digital signal reproducing apparatus comprising: an analog to digital converter for sampling and quantizing a reproduced RF (Radio Frequency) signal read from an optical recording medium in which address information is intermittently recorded as embossed pits and a recording groove has a wobble in accordance with a reproduced clock having a frequency which is one-half of a channel bit frequency and outputting an obtained digital RF signal; an offset compensation circuit for reducing an offset component in an amplitude direction from the digital RF signal and outputting the digital RF signal with the reduced offset component in the amplitude direction; a simplified interpolation filter for reconstructing a signal indicating a predetermined pattern recorded in the optical recording medium from the output signal of the offset compensation circuit and outputting the reconstructed signal; a first phase error detection circuit for obtaining a phase error in a section with the predetermined pattern in accordance with the output signal of the offset compensation circuit and an output signal of the simplified interpolation filter and outputting the phase error as first phase error information; a second phase error detection circuit for obtaining a phase error in a section other than the section with the predetermined pattern in accordance with the output signal of the offset compensation circuit and outputting the phase error as second phase error information; a smoothing filter for setting a feedback gain to each of respective values shown by the first phase error information and the second phase error information to reduce a magnitude of each of the values, obtaining a product of each of the values and the feedback gain corresponding thereto, smoothing a result, and outputting the smoothed result; and a clock generation circuit for generating the reproduced clock in accordance with the output signal of the smoothing filter.