APPARATUS AND METHOD FOR MODULATING WOBBLE SIGNALS OF OPTICAL DISK, AND APPARATUS AND METHOD FOR DEMODULATING THE SAME

摘要

PURPOSE: An apparatus and a method for modulating wobble signals of an optical disk, and an apparatus and a method for demodulating the same are provided to remove an algorithm and hardware for modulation frequency and phase discrimination. CONSTITUTION: First and second frequencies of an MSK(Minimum Shift Keying) wobble signal modulated and recorded at an optical disc as physical address information are coherently adjusted, so that peak points of the wobble signals are formed at points where each frequency changes. Signal levels at the peak points have direct relationship with bit data of the original bit data. In the case of demodulating the MSK wobble signal, a band pass filter(50) filters an analog wobble signal of a push-pull signal read from an optical disc in a predetermined frequency band for removing radio frequency noise components. An ADC(Analog-to-Digital Converter)(51) converts the filtered analog wobble signal into a digital wobble signal. A slope detector(52) monitors and detects a slope of the digital wobble signal. A peak detector(53) outputs a peak detecting signal by detecting a point where the detected slope is converted from negative to positive as a minimum peak point, and detecting another point where the detected slope is converted from positive to negative as a maximum peak point. A clock detector(54) detects periods of a level transit point for outputting a bit clock signal. A bit detector(55) detects a level value of the peak detecting signal at a falling edge of the bit clock signal.