PHASE DIFFERENCE DETECTION CIRCUIT AND ITS METHOD, PHASE COMPARATOR HAVING THE PHASE DIFFERENCE DETECTION CIRCUIT, PHASE LOCKED LOOP CIRCUIT HAVING THE PHASE DIFFERENCE COMPARATION CIRCUIT AND OPTICAL DISK DRIVE SERVO DEVICE USING THE PHASE LOCKED LOOP CIRCUIT

摘要

PROBLEM TO BE SOLVED: To shorten a processing time with a less memory and simple circuit constitution by calculating a first phase difference from prescribed bits of respective first bits of first and second digital signals and calculating a sine wave component correction value and a cosine wave component correction value from prescribed bit data of respective first bits. SOLUTION: A digital system phase comparator 52 is provided with a digital complex multiplier 521 and a digital phase difference detector 522, and the digital complex multiplier 521 inputs a digital tracking error signal TE shown as a sine wave function sin (α) of a phase angle (α) and a digital cross track signal CTS whose phase advances by 90 deg. for the tracking error signal TE and shown as a cosine wave function cos (α) of the phase angle (α), and calculates the phase differences between the digital input signals and a digital sine wave signal and a digital cosine wave signal from a digital voltage control type oscillator 56.