Patent ID: 7433289

Claim:
A frequency detection method for an optical disc bit data reproduction apparatus, the frequency detection method detecting a frequency of RF digital bit data used at the time of interpolation when digital bit data are detected from Radio Frequency (RF) signals used in an optical disc playback system, the method comprising: a primary frequency detection step determining status of input RF digital bit data frequency with respect to sampling frequency and correcting the sampling frequency to the frequency of the RF digital bit data in order to primarily detect frequency; a sync code detecting step detecting a sync code within a fixed window after the correction of the sampling frequency; and a secondary frequency detection step further correcting the sampling frequency using the number of pieces of bit data existing between sync codes, whenever sync codes are detected, if the sampling frequency is corrected to the frequency of the RF digital bit data within a predetermined range at the primary frequency detection step in order to secondarily detecting frequency, wherein the primary frequency detection step is performed such that the sampling frequency is corrected to be low if the sampling frequency is higher than the frequency of the input RF digital bit data and the sampling frequency is corrected to be high if the sampling frequency is lower than the frequency of the input data, thereby increasing a correction speed of the sampling frequency, and wherein the secondary frequency detection step is performed after the sync code has been successively detected within the window a specified number of times.