Patent ID: 7257071

Claim:
An apparatus which detects a frame synchronization signal from a digital data signal reproduced from an optical disc, the apparatus comprising: a synchronization signal detector, which detects and outputs a synchronization signal from the digital data signal; a main frame synchronization signal generator, which detects and outputs a first valid synchronization signal from the synchronization signal as an internal frame synchronization signal, and generates and outputs a first insertion synchronization signal as the internal frame synchronization signal, if the first valid synchronization signal is not detected during a predetermined first time period; a sub frame synchronization signal generator, which detects and outputs a second valid synchronization signal from the synchronization signal while the main frame synchronization signal generator generates the first insertion synchronization signal; and a first output unit, which outputs a frame synchronization signal in response to the internal frame synchronization signal and the second valid synchronization signal, wherein the main frame synchronization signal generator stops generating the first insertion synchronization signal in response to the second valid synchronization signal, and detects and outputs the first valid synchronization signal as the internal frame synchronization signal.