Patent ID: 7688687
Filing Date: 2010-03-30
Classification: G11B,H03L,H04L

Abstract:
1. A timing extractor in an information playback apparatus for extracting data and recording timing of the data from a playback signal, the timing extractor comprising: a clock generation section for generating a clock according to a set frequency dividing rate and outputting the generated clock; quantization means for quantizing the playback signal in accordance with timing of the output clock of the clock generation section and outputting the quantized signal; a frequency ratio calculation section for measuring either a specific pattern or an interval between two consecutively appearing specific patterns contained in an output sequence of the quantized signal from the quantization means, or both the specific pattern and the specific pattern appearing interval, in accordance with the output clock of the clock generation section, and calculating, based on a value obtained by the measurement, a frequency ratio between a playback frequency of the playback signal and a frequency of the output clock of the clock generation section; a phase correction amount calculation section for calculating the amount of phase correction for the output clock of the clock generation section with respect to the quantized signal from the quantization means; a control section for receiving the frequency ratio calculated by the frequency ratio calculation section and the amount of phase correction calculated by the phase correction amount calculation section, and calculating and setting the frequency dividing rate of the clock generation section and a cycle of the output clock of the clock generation section with respect to a playback cycle of the playback signal; and a pseudo-synchronous clock generation section for eliminating, based on an output from the control section, pulses of the output clock of the clock generation section to generate a pseudo-synchronous clock that is synchronized with the recording timing of the recorded data in a pseudo-manner, the output of the control section being the cycle of the output clock of the clock generation section with respect to the playback cycle of the playback signal.